10.2.1 The International Legal Framework Relating to Submarine Cables

An international element is required for the international legal framework relating to submarine cables to enter the picture. Usually this occurs because the cable passes through different maritime areas or zones of one or more coastal States. Submarine cables require a starting point and an end point from landing stations ashore. International cable systems require landing stations in the land territories of different coastal States. Before these stations are reached, submarine cables may transit maritime areas that are part of a coastal State’s territory and where it has sovereignty (archipelagic waters, internal waters, or the territorial sea); those areas that are subject to functional coastal State jurisdiction (the contiguous zone, the EEZ, and the continental shelf); areas beyond coastal State jurisdiction (the high seas and the international deep-seabed area); or a combination thereof. Depending on the submarine cable segment involved, the applicable international legal rules and the extent of coastal State authority vary.

Submarine cables are regulated by four international legal instruments: the 1958 Geneva Conventions on the Continental ShelfFootnote ³ and the High Seas,Footnote ⁴ UNCLOS, and the Convention for the Protection of Submarine Telegraph Cables (1884 Cable Convention).Footnote ⁵ Only the last of these is specifically designed for dealing with telegraphic cables, regulating them in the narrow context of their protection. Particularly relevant for States, however, is UNCLOS. That Convention has attracted close to universal participation, and its provisions on submarine cables have virtually all obtained customary status (Carter and Soons Reference Carter, Soons, Burnett, Beckman and Davenport2014, 332). This is because those provisions on cables in the 1958 Conventions on the High Seas and the Continental Shelf, which UNCLOS replicates, were already considered customary (Davenport Reference Davenport2012, 203). As background, when UNCLOS was negotiated at the Third Law of the Sea Conference, the use of submarine cables was on the decline owing to the increased use of satellites, which were cheaper and more reliable at that time (Carter et al. Reference Carter, Burnett, Drew, Marle, Hagadorn, Bartlett-McNeil and Irvine2009, 15). This changed after the final text of UNCLOS had been agreed upon in 1982. The real watershed moment came the following year, in 1983, with the creation of the internet (Ash Reference Ash, Burnett, Beckman and Davenport2014, 34). Fiber-optic cables and the internet became inexorably intertwined in that, through these cables, virtually all the video, voice, and data traffic for the internet were transmitted (see Section 10.1.1). A general implicit reference to the significance of submarine communication cables in UNCLOS can be distilled from one of the aims in the preamble: to strengthen “a legal order for the seas and oceans which will facilitate international communication.”

A key aspect of the legal rules for submarine cables is whether they land on an island or mainland territory of a coastal State. If such landfall is made by a cable in its territory, a coastal State has significantly greater authority over it than if it merely passes offshore. The extent of this authority would then not be confined to the cable segments physically located in its territory, including the territorial sea. This is an automatic corollary to the requirement that cables making a landing in the territory of the coastal State have its consent. To exercise that authority, coastal States may impose certain conditions on the cable and its landing, such as compliance with regulations on the route the cable takes, as well as associated environmental and labor laws. The effect of this is that the set conditions can also relate to those segments of cable systems that are in the EEZ, on the continental shelf, and possibly even beyond (Carter and Soons Reference Carter, Soons, Burnett, Beckman and Davenport2014, 335).

In this light, the provisions of UNCLOS are largely tailored to submarine cables that only pass through a coastal State’s maritime zones without making a landfall. The precise rights and obligations of States concerning transit cables vary with the maritime zone involved. For maritime areas that are part of the coastal State’s territory (that is, internal waters, archipelagic waters, and the territorial sea), the legal framework for submarine cables is straightforward: the coastal State has full regulatory authority over the laying, maintaining, and repairing of cables within these areas (Articles 2 and 49). This latter provision relating to archipelagic waters must be read in conjunction with Article 51, which provides that archipelagic States must respect in situ transit cables by allowing their repair, maintenance, and possible replacement upon receipt of notice. Coastal State authority applies in maritime zones under the coastal State’s sovereignty, regardless of how the cable is classified or its function. A clear picture also emerges for cables transiting areas beyond coastal State jurisdiction, such as the high seas and the international deep seabed. Article 87(1)(c) of UNCLOS grants all States the freedom to lay transit submarine cables in these areas, subject to Part VI of the Convention. That right is further strengthened in Article 112(1). While not explicitly mentioned in Article 87 or 112, repairing and maintaining transit submarine cables, including cable route surveying, are covered by the freedom of the high seas (Van Logchem Reference Van Logchem2014, 111–112). This view is based on the assumption that repair and maintenance are essential to the lawful use of the sea and inseparable from the freedom to lay transit submarine cables (Van Logchem Reference Van Logchem2014, 109, 112). A related question is whether attaching oceanographic sensors to submarine cables, which adds the functionality of data collection, could be considered part of the freedom to lay such cables (Strati Reference Strati2011). This question is further addressed in Section 10.2.3.

Regarding areas within coastal State jurisdiction (that is, the EEZ and the continental shelf), the international legal regime on submarine cables is more complex. Article 58(1) of UNCLOS grants the right to lay cables in these zones, but with certain limitations. The right to lay cables only applies to those transiting the EEZ or the continental shelf without making landfall. Although Article 79(1) of UNCLOS is silent on the right to repair and maintain transit cables, these have to be viewed as activities inherent in the right to lay such cables. Beyond that, in Article 79(2) and (5) there is explicit reference, respectively, to the maintenance and repair of in situ cables. Rights related to transit submarine cables must be exercised with due regard for in situ cables and pipelines and in a way that does not hamper their repair (UNCLOS, Article 79(5); Van Logchem Reference Van Logchem2014, 110, 118). A similar obligation of due regard in exercising cable rights in the EEZ and on the continental shelf flows from Article 58(3). This provision imposes on all States – which also extends to private actors engaged in cable activities (Van Logchem Reference Van Logchem2014, 100, 118) – an obligation to comply with laws and regulations of coastal States that are adopted in accordance with Part V of UNCLOS. Particularly relevant for cables are Article 79(2) and (4) (paragraph 3 is concerned with the delineation of pipelines), which allows for limitations to be imposed by coastal States on the right to lay transit cables of other States.

According to Article 79(2) of UNCLOS, the coastal State retains the option to take reasonable measures necessary to protect the exploratory and exploitation rights it has with regard to the continental shelf and any resources contained therein. Measures that would likely fall under this heading are those geared toward prohibiting cable laying in environmentally sensitive areas or areas reserved for hydrocarbon exploitation (Van Logchem Reference Van Logchem2014, 109). It follows from the same paragraph that coastal States cannot adopt regulations for pollution control in connection with cables located on their continental shelf; the background to reserving this right to pipelines lies in the fact that cables have virtually no detrimental impact on the marine environment (Carter et al. Reference Carter, Burnett, Beckman and Davenport2014). Article 79(4) states that Part VI leaves untouched that the coastal State can set conditions for cables that enter its territory. However, there are differing opinions on how much room Article 79(2) and (4) leaves for the coastal State to take measures that impose limitations on the right to lay transit submarine cables. The main bone of contention is whether the coastal State’s authority goes beyond setting conditions related to natural resources over which the State has sovereign rights (Beckman Reference Beckman2010, 6, 7; Davenport Reference Davenport, Schreiber, Kraska and Kwon2015b, 220–222). A general limitation is that measures taken may not amount to the right to lay, maintain, and repair submarine cables being effectively impossible to exercise (Van Logchem Reference Van Logchem2014, 109).

There is little attempt in UNCLOS to distinguish between different types of submarine cables, suggesting that its provisions apply to the full range of cables (Burnett Reference Burnett2006, 232; Nandan and Rosenne Reference Nandan and Rosenne1993, 270; Takei Reference Takei2012, 207–208). Only Article 113 specifies its scope of application to extend only to certain types of cables – that is, high-voltage power cables and telegraphic and telephonic communication cables. Despite the provisions in UNCLOS applying to cables broadly, specific types of cables will be subject to another set of rules due to their use and location, pursuant to which the coastal State may assume jurisdiction. For example, if a submarine cable is used for the sole purpose of transmitting data gathered through an MSR project in relation to the continental shelf, it would be under coastal State jurisdiction, and coastal State consent would be required prior to the cable being laid, in accordance with Article 246(1) of UNCLOS. The same analysis would apply by analogy to an out-of-service telecommunication cable that is modified to collect oceanographic data (variant (a) in Section 10.1.2), which may convert it to an MSR activity in the process.

Another example is a telecommunication or power cable connecting different installations on the coastal State’s continental shelf. Due to the direct link with the exercise of sovereign rights it has over natural resources and their exploitation, this author suggests that the cable would fall under coastal State authority (UNCLOS, Article 79(4); Davenport Reference Davenport, Schreiber, Kraska and Kwon2015b, 222–223). Outside of cables making a landfall and the limitations allowed for under UNCLOS, coastal States cannot assume jurisdiction over activities related to transit cables in the EEZ or on the continental shelf. However, in certain respects, the practice of some coastal States has moved in the opposite direction, in that they claim to have jurisdiction over the laying, maintaining, and repairing of transit submarine cables on the continental shelf (Ford-Ramsden and Davenport Reference Ford-Ramsden, Davenport, Burnett, Beckman and Davenport2014, 146–151). Limitations imposed by coastal States on the right to conduct activities in the EEZ and on the continental shelf related to transit telecommunication cables are a thorn in the side of industry. A main concern is that multiplying the functionality of active telecommunication cables will lead to coastal States increasingly exerting jurisdiction over cable-related activities, whereby further complications are layered onto existing ones (Bressie Reference Bressie2012, 24).

10.2.2 Marine Data Collection

Marine data collection encompasses a variety of activities conducted to the common aim of enhancing the knowledge of the marine environment (Roach Reference Roach, Nordquist, Long, Heidar and Moore2007, 542). These activities fall into different categories and include activities conducted in the framework of MSR, operational oceanography, hydrographic surveys, and military surveys (Van Logchem Reference van Logchem2021b). Depending on the activity data collected, it may be subject to the rules in Part XIII of UNCLOS. Complicating matters is that UNCLOS does not define MSR in Part XIII, nor anywhere else in the text for that matter. Several attempts by States participating in the Third Law of the Sea Conference to include a definition of MSR during the negotiations for the Convention failed, and States failed to reach an agreement (Soons Reference Soons1982, 199; Walker Reference Walker2012, 241–245). Attention was rather directed at designing the substantive rules pertaining to MSR, whereby its contours would be illuminated in the process and alleviate the need for States to agree on a generally accepted definition – or so was the thinking (Soons Reference Soons1982, 123–124). Nonetheless, in the absence of an express definition, much ink has been spilled on how to define MSR. The absence of a definition in UNCLOS has been lamented, including because that it would lie at the roots of the divergent State practice that emerged around MSR/oceanographic data collection and for the difficulties it has created for the employment of SMART cables (see, for example, Davenport Reference Davenport, Schreiber, Kraska and Kwon2015b, 249–250). Differences as to what constitutes MSR have ranged from States that fall on the extreme end of the spectrum – claiming that all forms of marine data collection fall within the jurisdiction of coastal States, including operational oceanography and hydrographic or military surveying – to, on the other end, coastal States that view their jurisdiction as being limited to MSR proper (Churchill et al. Reference Churchill, Lowe and Sander2022, 783–787).

Nonetheless, irrespective of the lack of a universally accepted definition of MSR and divergent State practice, the contours of what constitutes MSR are increasingly clear. An MSR activity is generally understood to have two components: first, the research activity is aimed at furthering the knowledge of humankind on the marine environment; and, second, the results are publicly disseminated (Soons Reference Soons1982, 124). Activities meeting this definition are within the authority of the coastal State, insofar as they occur within maritime zones over which it has sovereignty or jurisdiction. More specifically, the resulting picture is that MSR within the extent of the territorial sea is predicated on coastal State consent (UNCLOS, Article 245). This is further corroborated by Article 19(2)(j) of UNCLOS, which identifies the passage of a ship becoming non-innocent if it is involved in research or survey activities. Data that is gathered in passage for the sake of safe navigation of the ship (for example, the use of sonar to obtain information on ocean currents) remains beyond the reach of this provision (Soons Reference Soons1982, 149).

The conduct of MSR in the EEZ and on the continental shelf, as in the territorial sea, is subject to the consent of coastal States (UNCLOS, Articles 56(1)(b) and 246). Another similarity between the territorial sea and the EEZ/continental shelf is that the coastal State can impose conditions on the initiation and conduct of MSR projects. However, UNCLOS draws a distinction between two types of MSR projects in the EEZ and on the continental shelf: first, those projects for which the coastal State shall normally give its consent when a detailed application is made at least six months before the start of the project (Articles 248 and 249); and, second, MSR projects for which there is discretionary autonomy for the State to withhold its consent. In the latter case, a coastal State may, inter alia, exercise its discretion to withhold consent to MSR projects in the EEZ/continental shelf that hold significance for the exploration and exploitation of natural resources (Article 246(5)(a)), or envision the emplacement or operation of installations and structures (Article 246(5)(c)), or if the research involves drilling or setting off of explosives (Article 246(5)(b)). For all the categories of MSR, States seeking consent to conduct activities to this end will be under the additional obligations laid down in Articles 248 and 249 of UNCLOS. This includes offering the coastal State the opportunity to be part of the MSR project (Article 249(1)(a)) and making the collected information available as soon as practically possible (Article 249(1)(e)).

On the high seas, there is the right for all States to conduct MSR projects (Article 87(1)(f)), subject to the two parts of UNCLOS dealing with the continental shelf (Part VI) and MSR (Part XIII). Along similar lines, in the international seabed area, States and competent international organizations have the right to conduct MSR. This aligns with Part XI of UNCLOS, particularly Article 143, which requires MSR projects to be for peaceful purposes and to benefit all humankind. Beyond these two requirements, in both the high seas and the international seabed area, the right to conduct MSR has to be exercised with due regard to the rights of other States and other activities occurring in the international seabed area (Article 87(2)). Of further relevance is Article 258, which is concerned with the deployment of research installations or equipment in the marine environment. This provision may apply to SMART cables, due to the similarities they bear to installations in terms of their relative permanency (see Section 10.2.3).

From the range of activities falling within the ambit of marine data collection, could oceanographic data collection be an alternative categorization for SMART cables (Davenport Reference Davenport, Schreiber, Kraska and Kwon2015b, 224)? Two components are attached to “operational oceanography”: it must involve the routine collection of oceanographic data, which subsequently is made immediately and generally available. It may be defined as follows: “an activity of systematic and long-term routine measurements of the seas and oceans and atmosphere, and their rapid interpretation and dissemination” (Davenport Reference Davenport, Schreiber, Kraska and Kwon2015b, 234). Although the obtained data may produce knowledge similar to the data gathered under the umbrella of an MSR project, in that it benefits humankind as a whole, the main usage of operational oceanographic data is in the realm of the safety of navigation (Kraska Reference Kraska, Nguyen and Dang Vu2024, 44–45). Beyond that, general controversy surrounds this category of oceanographic data collection, or – as it is regularly referred to – operational oceanography. One main issue is whether this routine collection of oceanographic data is really an MSR activity in disguise (Mateos and Gorina-Ysern Reference Mateos and Gorina-Ysern2010; Whomersley Reference Whomersley, Zou and Telesetsky2021, 29). These differences were mirrored in the practice of States in relation to the “Argo Project” pursuant to which several thousands of monitoring devices that gathered marine meteorological data were deployed on the high seas (Davenport Reference Davenport, Schreiber, Kraska and Kwon2015b, 234–235). However, as these devices freely drifted throughout the sea, they sometimes entered into the EEZs of coastal States. Some coastal States were concerned and deemed them to be engaging in MSR, for which coastal State consent is required (Mateos and Gorina-Ysern Reference Mateos and Gorina-Ysern2010). Both the controversial status of the collection of oceanographic data (whether or not it qualifies as MSR) and the specifics of SMART cables put into doubt whether they can be easily brought under this rubric. This is because the data collected through these SMART cables is not immediately disseminated, and nor is it collected with the explicit aim of enhancing the safety of navigation. Another aspect that makes it difficult to bring SMART cables under the reach of this “operational oceanography” is that, in contrast to ships or floating equipment routinely collecting data, SMART cables are of a more permanent character, as they are on the seafloor. All this points in the direction that, from the range of activities that equally fall within the scope of marine data collection, SMART cables are an MSR activity (Carter and Soons Reference Carter, Soons, Burnett, Beckman and Davenport2014, 335).

10.2.3 The Future of SMART Cables

A logical corollary to SMART cables being a technological development that came after UNCLOS is that none of its provisions have been specifically tailored to this type of cable. This does not render UNCLOS inconsequential, however, as it has the capacity to continue to apply to new technological developments. The legal regimes in Parts VI and XIII are relevant to SMART cables (Strati Reference Strati2011). SMART cables are in situ in the marine environment and have this same environment as their object on which to collect data, beyond transporting international communications, which clearly raises the specter that they fall within coastal State jurisdiction, depending on their location.

More specifically, on the high seas and in the international seabed area, there exist the two freedoms to lay transit cables (UNCLOS, Article 87) and conduct activities in the framework of MSR (Articles 87(1)(f), 256, and 257). By the same token, coastal States cannot claim jurisdiction over SMART cables. Rather, the jurisdictional competence lies with “the national State of the entity laying or using the cable” (Carter and Soons Reference Carter, Soons, Burnett, Beckman and Davenport2014, 336). In stark contrast, in areas that are part of the territory of the coastal State (internal waters, archipelagic waters, and the territorial sea), both the conduct of MSR and submarine cable activities fall within the sovereignty of the coastal State, allowing it to regulate SMART cables in a way it sees fit (Carter and Soons Reference Carter, Soons, Burnett, Beckman and Davenport2014, 334).

It is a tale of different worlds colliding for SMART cables that transit a coastal State’s EEZ or continental shelf. While submarine cables transiting the EEZ or continental shelf are largely placed outside the jurisdiction of the coastal State, apart from some limitations related to natural resources, MSR in the EEZ and on the continental shelf falls under the jurisdictional competence of the coastal State (see Sections 10.2.1 and 10.2.2).

Further, an argument has been made that if a submarine cable placed on the seabed collects data (that is, if it is a SMART cable), besides constituting MSR, it falls in the specific category of MSR projects for which the coastal State concerned would have the discretionary autonomy to withhold its consent when an application to that end is made (Carter and Soons Reference Carter, Soons, Burnett, Beckman and Davenport2014, 335). At the root of this argument lies an assumed similarity between a SMART cable and a structure: that is, their “semi-permanent character,” which would bring it under the reach of Article 246(5)(c) of UNCLOS (Carter and Soons Reference Carter, Soons, Burnett, Beckman and Davenport2014, 335). This argument that the cable has to be considered a structure has been extended by analogy to cables that collect data landing on shore or entering a coastal State’s territorial sea. If SMART cables would be considered a research structure, and given that they are placed on the seabed to remain in place for a longer period of time, the coastal State would have exclusive jurisdiction over the cables by way of Articles 60 and 80 of UNCLOS. Nonetheless, different views have been held in this regard, with Bressie assuming that definite judgment around the status of SMART cables as being also subject to the MSR regime cannot be made based on UNCLOS (Bressie Reference Bressie2012, 20). Underpinning this argument is the failure of UNCLOS to address the precise meaning of both “MSR” and a “submarine cable,” leaving the status of the latter up in the air in the absence of judicial pronouncement and/or customary international law having developed in either direction (Bressie Reference Bressie2012, 20).

As a general rule of thumb, legal difficulties and uncertainty tend to come to the forefront for SMART cables in the EEZ and concerning the continental shelf. By way of contrast, MSR is a high-seas freedom beyond areas of national jurisdiction. The argument that outfitting cables with sensors is absorbed by the freedom to lay transit submarine cables under Article 87 of UNCLOS, which by way of Article 58(1) of UNCLOS similarly applies in the EEZ, has little merit, particularly if account is taken of the fact that the oceanographic sensors are purposely added to telecommunication cables to provide them with the added functionality of data collection, which is a fundamentally different activity from transporting international communications. Attaching sensors is also not entangled with the right to lay transit cables in a way the two could not be seen in isolation, as is, for example, the case with repairing or maintaining a transit cable, or conducting a cable route survey prior thereto, which are all necessary components to be able to exercise this right. Viewed in this light, nor can the attaching of oceanographic sensors to telecommunication cables located in the EEZ be seen as a use related to the operation of such cables (UNCLOS, Article 58(1); Strati Reference Strati2011). Considering the above, the de lege lata suggests that MSR is the most proper categorization for SMART cables, whereby a need for obtaining coastal State consent is activated prior to their employment in certain parts of the seas (Carter and Soons Reference Carter, Soons, Burnett, Beckman and Davenport2014, 335).

10.3.1 A Flawed International Legal Regime?

Given their critical nature, also for society, submarine telecommunication cables require adequate protection (Beckman Reference Beckman, Burnett, Beckman and Davenport2014, 281; UNGA 2011, 121, 2023, 125). Irrespective of it being mostly private actors who conduct activities related to such cables, States retain a critical role in this respect. Among others, they have the responsibility to ensure that cable systems are sufficiently resilient, that such systems meet safety and security requirements, and that repairs can be made as swiftly as possible when such infrastructure is damaged. The need for State involvement has become only more pressing with submarine cables increasingly being viewed through the specter of security. As discussed in Section 10.3, this security angle for States is clearly brought into focus, as instances are on the rise where there is at least the suspicion of cables being intentionally targeted – for example, in the Taiwan Strait. Another example is the Balticconnector incident of 2023, when several submarine telecommunication cables were cut by the NewNew Polar Bear, flying the flag of Hong Kong (Ringbom and Lott Reference Ringbom, Lott and Lott2024, 155). But is the international legal framework adequately equipped for ensuring their protection?

A key feature of the international legal framework pertaining to the protection of submarine telecommunication cables is that it is antiquated (Beckman Reference Beckman2010, 7; Takei Reference Takei2012, 207–208; Van Logchem Reference van Logchem2021a). There is a handful of provisions in UNCLOS on cable protection in the EEZ and the high seas – that is, Articles 113–115. These provisions have their roots in the 1884 Cable Convention, which marks the birth of the legal regime for the protection of submarine cables. The 1884 Cable Convention bears the hallmarks of its time, among which is its focus on telegraphic cables. It formed the culmination of several diplomatic efforts that began in earnest in 1882, which was when cables were first laid on the seabed (Burnett et al. Reference Burnett, Davenport, Beckman, Burnett, Beckman and Davenport2014a, 65). Under the 1884 Cable Convention, competing fishing activities taking place outside the “territorial waters” of coastal States were recognized as one of the preeminent threats to cables. The 1884 Cable Convention is unique, being the only international treaty exclusively concerned with submarine cables. However, it cannot be considered overly successful, as only forty States became parties to it. Despite its limited success in attracting State participation, the 1884 Cable Convention has shaped the subsequent direction of the international law on the protection of submarine cables. This is reflected in the fact that the relevant provisions in UNCLOS (Articles 113–115) are lifted almost verbatim from the 1884 Cable Convention.

The scope of application of Articles 113–115 of UNCLOS on cable protection is limited to areas lying beyond the extent of the territorial sea. As a corollary, UNCLOS does not contain a provision obligating coastal States to adopt laws and regulations to protect submarine cables within their territory, including in port or in the territorial sea. It has been alleged that this was underpinned by the thinking at the Third Law of the Sea Conference that there was no need to introduce a provision on cable protection in the territorial sea, as States themselves would recognize the importance of properly regulating this domestically (Beckman Reference Beckman, Burnett, Beckman and Davenport2014, 287). Contrary to expectations, however, this has not been reflected in the practice of all States (Beckman Reference Beckman, Burnett, Beckman and Davenport2014, 287).

Under Article 113, the breaking or injuring of a submarine cable located beneath the high seas (or the continental shelf/EEZ) through willful or culpable negligence is addressed. It places the burden of regulation on the flag state or on a State that otherwise has jurisdiction over the persons involved. Conduct that is calculated or likely to result in the breaking or injuring of a submarine cable is also caught under this provision. This is an innovation in UNCLOS, as the provisions developed along similar lines in both the 1884 Cable Convention (Article II) and the 1958 Convention on the High Seas (Article 27) lack this language. In its commentary to Article 62 of the 1956 Draft Articles on the Law of the Sea, whose content resembles Article 113 of UNCLOS, the International Law Commission indicated that a precondition for culpable negligence is that the damaged cable has been clearly marked on charts (ILC 1956, 294). From Article 114 of UNCLOS flows the obligation for States to regulate when, in the laying or repairing of a new submarine cable, a break or injury is caused to an in situ submarine cable for which the owner of the new cable is liable. The extent of liability is confined to the repair costs of the damaged cable; for other types of damage, no civil liability exists. Article 115 of UNCLOS approaches the issue from a different angle: that is, if, in attempting to avoid damaging a submarine cable, an anchor, net, or fishing gear must be sacrificed, the cable owner, assuming that it has “taken all reasonable precautionary measures,” will be indemnified.

Different weaknesses around cable protection arise depending on whether it involves maritime areas that are within functional coastal State jurisdiction (the EEZ and the continental shelf) or under coastal State sovereignty – for example, the territorial sea. Because coastal States enjoy sovereignty over their territory, various options to protect cables are part of their arsenal in the territorial sea, including designating areas where ships cannot anchor, or setting a cable burial requirement. The other side of the sovereignty coin is that States are not obligated to exercise any of the powers they have by international law, leaving this to their own discretion. As many of these cables in the territorial sea are likely to make a landfall, coastal States have an interest in ensuring that these cables enjoy adequate protection.

Outside the territorial sea, the picture fundamentally changes, in that more emphasis is placed on what often will be the role of the flag State. Tied to this, the challenges that have arisen in respect of flag State jurisdiction and control, including around flags of convenience, rise to the fore (Van Logchem Reference van Logchem, Smits, Husa, Valcke and Narciso2023, 421–428). Despite the obligations in Articles 113–115 of UNCLOS to introduce domestic legislation, State practice differs on this point. Relevant laws may not exist; or, alternatively, if laws are on the books, they may exhibit deficiencies or be out of pace with the present times (House of Lords 2022, 77; Wargo and Davenport Reference Wargo, Davenport, Burnett, Beckman and Davenport2014, 262–263). Another issue is whether these laws are actually enforced by, for example, flag States, as significant strides would be made if the existing law was “effectively implemented and enforced by all States” (Mensah Reference Mensah and del Castillo2015, 739).

11.2.1 Shipwrecks and Cultural Heritage

Shipwrecks can offer a vast amount of information to those with the capabilities, time, and resources to conduct archaeological studies. With the advancement of technology, scientific expeditions have searched shipwrecks for signs of potentially polluting substances, the presence of marine organisms, and to gain an understanding of past human behavior (NOAA 2024b). Given that shipwrecks are often accidental, they offer a view into the social, cultural, and economic aspects of past experiences at a specific moment in time (NOAA 2024b). This means that those conducting archaeological studies of warships can also gain knowledge of their past armament and military history (Hayden Reference Hayden2023). Marine archaeologists have described shipwrecks as time capsules through which careful study can allow access to previously inaccessible stories and artifacts. Depending on the wreck site, tangible items may provide a cultural link to a State other than the vessel’s flag State. This introduces an added layer, given that a separate State may have an interest in the recovery of items through a cultural link, an interest in the preservation of the items, or an interest in the management and decisions regarding the wreck site.

The discovery of shipwrecks is not always the result of planned activities. Often, shipwrecks are located accidentally during environmental monitoring studies or as a serendipitous occurrence. There are times when it is necessary to conduct studies to gain a better understanding of certain landscapes ahead of a project, such as mapping exercises for underwater cables and offshore wind projects, in order to assess the potential for damage (Pater Reference Pater, Bailey, Galanidou, Peeters, Jöns and Mennenga2020). There have been instances where shipwrecks off the coast of a country have been stumbled upon during unrelated activities. The role of the coastal State remains the same regardless of whether a shipwreck was discovered through a planned archaeological expedition with appropriate permits, or accidentally without the proper equipment or resources. This is important to note, since States may consider shipwrecks to hold valuable cultural heritage significance, which can then alter the original scope of a project, or the role of all States involved with the shipwreck. Environmental assessments is one type of activity through which shipwrecks can be discovered, although, should a shipwreck be discovered by government or military vessels, States are not obligated to share that information under Article 13 of CPUCH, which states:

The discovery of a shipwreck can not only lead to a plethora of information; it can also be culturally significant for numerous States; it can help gain knowledge about a particular time in history; and it can offer acknowledgment of a final resting site. The exemption of government ships from alerting a coastal State of an underwater cultural heritage discovery can be an area for further study, as it potentially limits coastal State access, future studies, and security.

Meanwhile, discoveries of shipwrecks in an area where there are planned activities involve a question as to whether consent from the flag State of the sunken vessel – if it is different from that of the coastal State – would be required to move forward with such activities. Expanding coastal projects can include “trawling, dredging, offshore oil and gas explorations and port construction,” which may place undiscovered shipwrecks at greater vulnerability from destruction (Ridwan Reference Ridwan2019, 1623). The discovery of shipwrecks within the territorial sea, contiguous zone, or EEZ that have separate flag and coastal States can lead to discussions over activities that may interact with the shipwreck and surrounding ecosystem. As highlighted, “once a site or its artifacts are damaged or haphazardly removed, there is no way to access its information and recreate the story it might have told” (NOAA n.d.). The importance of cultural heritage connects to the untold stories that each shipwreck inherently contains. One shipwreck may hold significance for numerous States, and it is important to consider how States interact through existing international legal agreements, such as UNCLOS and CPUCH, when it comes to newly discovered shipwrecks with links to more than one State. The following section will discuss the role of emerging technologies in greater depth, followed by an analysis bridging cultural heritage and the ownership of shipwrecks.

11.3.1 Side-Scan Sonar

One technology to consider is the use of side-scan sonar. The application of side-scan sonar for underwater archaeological purposes has been actively used in the field since the 1960s (Goncharov Reference Goncharov2016). As this technology has continued to develop, it has become an increasingly important tool for the field of underwater archaeology. Side-scan sonar works by emitting and receiving acoustic pulses to aid in mapping the seafloor (NOAA 2002). These acoustic pulses can be emitted at different frequencies, ranging from 50 to 500 kilohertz, depending on the necessary breath and clarity (NOAA 2002). The pulses captured through this method are then used to create an image of the seafloor with shipwrecks and sites appearing in a darker shade than the seabed. One of the benefits of side-scan sonar is its ability to create 3D images of shipwrecks (Goncharov Reference Goncharov2016). It is also considered to be a less costly alternative to robotic technologies.

Scholars have noted the possible growth of side-scan sonar to continue developing through the use of global positioning systems for higher navigation and geographic references (Goncharov Reference Goncharov2016). One consideration between the use of side-scan sonar and global positioning systems to aid in the discovery of shipwrecks is the potential for conflict over access to the precise coordinates of a shipwreck. There are cases where multiple States having access to shipwreck coordinates could be considered potentially problematic, such as that of the San José, where Colombia has decided to keep private the precise coordinates of the shipwreck for security purposes. Another case involves the location of a French warship within US territorial waters (Gates Reference Gates2019) that was kept hidden. Similarly, the location of the Geldermalsen shipwreck has yet to be released publicly for fear of potential looting (Looram et al. Reference Looram and Lindley2024). These cases highlight how certain technologies used to locate and study shipwrecks can introduce potential security risks over sharing geographic details.

There have also been studies that take side-scan sonar a step further through its interaction with AI to detect shipwrecks from side-scan sonar imagery. A study conducted by the University of Michigan, AI4Shipwrecks, considers how machine learning can be utilized to uncover shipwrecks from side-scan sonar data (Sheppard et al. Reference Sheppard, Sethuraman, Bagoren, Pinnow, Anderson, Havens and Skinner2024). The use of AI may impact the amount of time necessary to identify shipwrecks, which can heighten interactions between underwater archaeology, UNCLOS, and CPUCH, as will be discussed in the following sections.

11.3.2 ROVs, AUVs, and USVs

Another technique to consider is the use of USVs, ROVs, and AUVs (NOAA 2024a). While side-scan sonar is a widely used technology within underwater archaeology, it is often deployed through the use of an USV. It is beneficial to cover how these technologies can aid in the discovery and study of shipwrecks.

USVs are used within multiple fields for numerous purposes, and they can be used to reach depths of up to 6,000 m (Merkusheva Reference Merkusheva2020). While the depth an unmanned vehicle can reach is impressive, it is also rare for an archaeological study to be completed within a single expedition, as it is common for teams to return to the same shipwreck multiple times to conduct studies and gain a better understanding of the area. Archaeological studies often include multiple AUVs and ROVs during a single mission, which can be costly but effective (Merkusheva Reference Merkusheva2020).

A specific case of the effective use of AUVs in locating wrecks is the discovery of the ARA San Juan submarine in 2018. The private company Ocean Infinity successfully located the wreck using five AUVs and two ROVs connected to a research vessel (Song Reference Song2023). The search for the submarine included collaboration between nineteen countries, and the official identification of the submarine was made through the use of an ROV (Villán Reference Villán2019). While the submarine discovered in this case would not fall under CPUCH’s 100-year time period in order to be designated a protected site, it is acknowledged as a memorial by Argentine officials. The submarine wreck site was found approximately 600 km east of Comodoro Rivadavia, off the coast of Argentina (Ocean Robotics 2018). This highlights Argentina’s role as the flag State of the submarine, with the absence of a separate coastal State given that the wreck was found within the high seas. This case provides an example of international collaboration in locating a potential wreck in times of stress and emergency, which differs from planned archaeological studies, although both include the use of highly advanced technologies.

USVs, ROVs, and AUVs introduce another issue to consider with legal implications distinct from the use of side-scan sonar and imaging technologies. This is centered on the fact that USVs, ROVs, and AUVs can increase human activity within previously challenging environments. It is worth noting the potential damage to archaeologically significant sites and wrecks caused by these vehicles, which can be explored in greater depth through additional research. USVs have been used in tandem with manned vehicles for the discovery of different shipwrecks through “launching, recovery, positioning, battery charging, and data transfer” (Zwolak et al. Reference Zwolak, Wigley, Bohan, Zarayskaya, Bazhenova, Dorshow, Sumiyoshi, Sattiabaruth, Roperez, Proctor, Wallace, Sade, Ketter, Simpson, Tinmouth, Falconer, Ryzhov and Abou-Mahmoud2020, 6). A goal of combining these technologies is to increase the level of coverage to be studied and maximize the study area (Roman and Mather Reference Roman and Mather2010). It is beneficial to maximize the study area, as it can present additional information, although it may be questionable from a legal perspective should the proposed study expand into multiple maritime zones.

There is also the issue of the amount of time it takes to conduct an effective study when using USVs and ROVs (Roman and Mather Reference Roman and Mather2010). Advantages of using robotic vehicles include their ability to “carry cameras, video cameras and acoustic sensors to take optical and acoustic images of the site” (Conte et al. Reference Conte, Gambella, Scaradozzi and Zanoli2009, 177). This reduces the instances of physical divers needed to survey a site, and while costly, it can provide highly accurate data over a larger area (Conte et al. Reference Conte, Gambella, Scaradozzi and Zanoli2009, 177). USVs and autonomous vehicles also fall under a distinct legal area compared to research vessels under UNCLOS. A limitation to the use of these technologies is within shallow waters, where they may not be as beneficial as in deep waters (Goncharov Reference Goncharov2016). An increasing number of expedition teams continue to employ multiple ROVs and AUVs for their efficiency, accuracy, timeliness, and ability to view and recover items from depths inaccessible to humans. Subsea vehicles allow for the potential of human interaction, although this presents changes that were not in practice at the time of the creation of Articles 149 and 303 of UNCLOS. These types of technologies have become standard practice for locating shipwrecks within deeper waters, and it will be important to ensure that existing practices over the legality of accessing shipwrecks in foreign waters continue to emphasize the importance of underwater cultural heritage and the preservation of wrecks.

11.3.3 3D Imaging and Photogrammetry

Three-dimensional images of the seafloor, in addition to containing outlines of shipwrecks, can be beneficial for coastal States in gaining access to a better understanding of the topography of their coastal waters. In addition to side-scan sonar, there have been innovations in the use of other 3D laser and scanning technologies (McCarthy et al. Reference McCarthy, Benjamin, Winton, van Duivenvoorde, McCarthy, Benjamin, Winton and van Duivenvoorde2019). Three-dimensional scanning systems have played a role in the documentation of cultural heritage, which may work in tandem with CPUCH (Bräuer-Burchardt et al. Reference Bräuer-Burchardt, Munkelt, Bleier, Heinze, Gebhart, Kühmstedt and Notni2023). The combined use of side-scan sonar and 3D scanning technology has made it possible to create more accurate documentation of objects on the seabed (Bräuer-Burchardt et al. Reference Bräuer-Burchardt, Munkelt, Bleier, Heinze, Gebhart, Kühmstedt and Notni2023). The use of traditional sonar technology helps create an image of the seabed. However, scholars have noted that “these shipwrecks on the seafloor usually appear as low elevation – high texture seabed features, such as many other small seabed features, with the wooden frame most often disintegrated and the cargo, mainly amphorae, dispersed around the wreck” (Ferentinos et al. Reference Ferentinos, Fakiris, Christodoulou, Geraga, Dimas, Georgiou, Kordella, Papatheodorou, Prevenios and Sotiropoulos2020, 7). The material with which the vessels were built also impacts their visibility when documented through 3D imaging technology.

Additional advancements in this area have centered on ways to capture images with greater clarity to aid in the identification of vessels and artifacts. Three-dimensional images as a result of side-scan sonar are helpful in capturing more detailed information for shipwrecks on the seabed, as compared to other versions of sonar technologies. Advanced photogrammetry has aided researchers in studying deepwater sites after returning to shore in order to identify and differentiate between objects to determine the flag State of origin, as was seen through the discovery of the US submarine S-28 (Hydro-International 2020).

ROVs, AUVs, USVs, sonar, and 3D imaging technologies can shift parts of the archaeological study of shipwrecks by decreasing the amount of time required at sea and increasing access to more accurate data. However, discussing how this interacts with UNCLOS and CPUCH is important, since these regimes include distinct rights and access with regard to archaeological objects.

11.4.1 United Nations Convention on the Law of the Sea

UNCLOS references underwater archaeology within Articles 149 and 303. Each article centers on the role of States pertaining to objects of an archaeological or historical nature found within different maritime zones. Articles 33 and 303 focus on activities within the territorial sea and the contiguous zone, while Article 149 focuses on the Area. There is a noticeable gap regarding archaeological objects found within the EEZ.

Article 303 (“Archaeological and historical objects found at sea”) states in part:

1. 1. States have the duty to protect objects of an archaeological and historical nature found at sea and shall cooperate for this purpose.

2. 2. In order to control traffic in such objects, the coastal State may, in applying article 33, presume that their removal from the seabed in the zone referred to in that article without its approval would result in an infringement within its territory or territorial sea of the laws and regulations referred to in that article.

While Article 303 does not directly reference shipwrecks, it can be expected that shipwrecks would fall under the phrase “objects of an archaeological and historical nature,” although there is no clear definition of what is considered to be an object of an archaeological nature. A focus is placed on the removal of objects from the seabed, and the article does not suggest other areas of importance, such as the examination of underwater objects. There is no direct mention of the role of the flag State concerning archaeological objects, as only the coastal State is referenced regarding its sovereignty over the waters in which the objects are located.

The focus on the control of traffic for the removal of objects hints at the likelihood of there being interest in the found objects from multiple States. The reference to Article 33, which focuses on the contiguous zone, notes that objects taken from this area without the consent of the coastal State would equal infringement upon their sovereign rights. This encompasses shipwrecks found within the territorial sea and contiguous zone, although there is a noticeable gap concerning the EEZ. The lack of a clear designation of rights for flag States and coastal States over shipwrecks found within the EEZ is an area to consider with the increasing number of shipwreck discoveries within this area.

Contrary to CPUCH, UNCLOS does not set a specific time period for the designation of shipwrecks as being archaeologically or historically significant. CPUCH states that an object must be underwater for a minimum of 100 years in order to be considered underwater cultural heritage and available for protective measures. Scholars have discussed whether UNCLOS can be interpreted to include a time period of 50, 100, or 200 years for objects to be considered archaeologically significant, based on time periods included within domestic instruments (Cottrell Reference Cottrell1994).

Article 149 (“Archaeological and historical objects”) states:

Thus, Article 149 includes three potential States that could have preferential rights over archaeological objects: the State of origin, the State of cultural origin, and the State of historical and archaeological origin. It is worth considering when and how these States may be distinct, as scholars have noted that there is no clear hierarchy within this Article to designate which States would gain ownership in the event that multiple States are involved (Henn Reference Henn2012). Scholars have argued that the use of the phrase “for the benefit of mankind as a whole” leads to an interpretation that underwater wrecks have “a commonness of ownership and benefit of shipwrecks with archaeological significance” (Cottrell Reference Cottrell1994). It echoes the goal of Article 303 in the preservation of objects, although there are no in-depth details concerning how objects should be preserved or disposed of. Scholars have also mentioned that “preferential rights suggest that one nation has a priority, but that there are simultaneous rights in other nations” (Cottrell Reference Cottrell1994). This connects to the idea that multiple States can have a role in, and active claims to, shipwrecks located outside of their national waters. However, Article 149 centers only on objects found within the Area, which encompasses the seabed beyond the continental shelf. When considering a map of the maritime zones referenced in UNCLOS, the Area would include not objects located within the EEZ but rather those below the water column of the high seas. The number of shipwrecks to be discovered may continue to increase in future years due to technological advancements in exploring the deep ocean. It is, therefore, helpful to consider the potential interaction between the State of origin, the State of cultural origin, and the State of historical or archaeological origin for vessels located and identified within multiple maritime zones.

Articles 33, 303, and 149 offer guidance for States to consider when making decisions on activities related to underwater sites or shipwrecks of historical or cultural interest. The overarching aim centers on collaboration to conserve, protect, or dispose of archaeologically significant objects and artifacts. An example of effective international collaboration can be seen through the discovery of the Titanic shipwreck. The UK was the original flag State of the Titanic, which was discovered by a team of divers within the high seas, off the coast of Canada in the North Atlantic. This is a well-known and much-studied case, leading to changes in international legislation, such as through the Safety of Life at Sea Convention.Footnote ³ The discovery of the Titanic shipwreck was possible through the use of Argo, an unmanned vehicle capable of reaching depths of up to 6,000 m and capturing images in challenging environments, as well as other deep-sea exploration technologies (WHOI 2024). However, it is significant that it was discovered within the high seas, as most newly discovered shipwrecks tend to be located within coastal waters.

Overlapping interests in ownership and preferential rights may be heightened when shipwrecks are thought to have precious gems, jewels, and stones on board. While all shipwrecks can be considered to hold significant cultural heritage for a variety of reasons, the presence of cargo and artifacts may affect how they are viewed by States. There are conflicting flag State and coastal State claims to the San José shipwreck by Colombia, Spain, Peru, a private company from the US, and Indigenous groups from Bolivia. Each of these States cites distinct reasonings for its claims to ownership over the artifacts surrounding the shipwreck. Colombia centers its claim on the fact that the shipwreck is located within Colombian waters and is part of its cultural heritage (Tumin and Glatsky Reference Tumin and Glatsky2024). Meanwhile, Spain claims that it should have access to the shipwreck since it is the original flag State, it has sovereign immunity, and it is the resting site of more than 600 Spanish sailors. Peru and several Indigenous groups claim ownership over the artifacts surrounding the shipwreck, given that colonial powers took the gold, silver, and emeralds from Peruvian, Bolivian, and Colombian mines worked by Indigenous people (Pinedo Reference Pinedo2024). A private salvage company based in the US claims ownership over content found on board given its claim to have discovered the shipwreck in 1980, years ahead of the discovery by the Colombian Navy. Sections of these differing claims have been taken to the Permanent Court of Arbitration, particularly cases between Colombia, Spain, and the US (Chen and Rios Reference Chen and Rios2024). This case highlights how the State of origin, the State of cultural origin, and the State of historical and archaeological origin have placed claims over the wreck. Article 149 mentions preferential rights, although there is insufficient expansion on these rights to gain a clear understanding of how they would impact a State’s claims.

This issue is further complicated by the fact that Colombia has not ratified CPUCH, while Spain has urged that the San José be considered as a protected site given its role as a resting place. This leads into the question of how technologies, and the inherent increased access, impact the designation and enforcement of shipwrecks as gravesites. While shipwrecks can be thought of as gravesites, they are also considered homes to marine ecosystems, materials to be exploited, and locations for potential bilateral cooperation or conflict. UNCLOS addresses a starting point for objects found within the territorial sea, the contiguous zone, and the Area, yet it leaves vague aspects of the management and ownership of shipwrecks. CPUCH was designed to resolve some of the uncertainty, but it has not been universally accepted.

11.4.2 Convention on the Protection of the Underwater Cultural Heritage

CPUCH, which entered into force in 2009, currently has eighty-one State parties. While fewer States have ratified CPUCH as compared to UNCLOS, the Convention continues to be relevant when it comes to the protection of the underwater cultural heritage. CPUCH has aided in the protection and preservation of shipwrecks and archaeologically significant sites across various areas of the ocean. One of its main focuses is the preservation of underwater cultural heritage, which is defined in Article 1(1)(a):

This Convention differs from UNCLOS in that it provides greater details on archaeologically significant objects, including a specified time period for which an object must be underwater in order to be considered underwater cultural heritage. The 100-year time period can aid in the designation of warships as underwater cultural heritage when more than one State is involved. There are existing domestic regulations governing the protection of shipwrecks, whether due to their understanding as gravesites or to the goal of limiting disturbance, and CPUCH serves to fill a gap in the management of shipwrecks that may involve multiple States. These issues become more complex as conflicts over the ownership of shipwrecks and their designation as gravesites arise, and when the States involved have not formally adopted the Convention.

In addition, underwater cultural heritage can be separated into tangible and intangible heritage. Shipwrecks and artifacts are considered tangible pieces of underwater cultural heritage, while intangible heritage would include oral stories and traditions passed down through generations (Micronesia 2024). Scholars have referenced how finding the location of certain shipwrecks originated through local knowledge and stories from fishermen and local inhabitants (Finney Reference Finneyn.d.). Local knowledge, combined with the technological capabilities of ROVs and AUVs, has led to the discovery of several wrecks. The argument in favor of the role of intangible cultural heritage as related to shipwrecks touches on the importance of oral stories in the discovery stage. This differs from UNCLOS, which does not reference tangible or intangible underwater cultural heritage when considering archaeological objects.

Article 7(3) of CPUCH states:

The role of the coastal State, as referenced in Article 7, is to inform the flag State of the discovery of an identifiable vessel within its territorial sea. There are no additional details provided on the continued role of the coastal State, such as to alert the flag State of future proposed activities that may impact the vessel. This can be challenging if the coastal State would need authorization from the flag State prior to conducting activities that may interfere with the sunken vessel. Balancing these varied interests over shipwrecks across maritime zones is important to ensure that wrecks are not unintentionally disturbed.

In addition to the enforcement of guidelines for known wrecks, it is also imperative to have oversight by the coastal State over expeditions to uncover potential wrecks. There have been cases where private divers have found shipwrecks within coastal waters and did not alert the national government as necessary under international customary law and domestic policy in certain States. In France, a group of commercial divers located the wreck of the Prince de Conty off the coast of the island Belle-Île-en-Mer in 1974, yet did not alert the French authorities of the wreck, preferring to keep it hidden (Mashberg Reference Mashberg2022). Years later, gold ingots recovered from the wreck were located in the US marketplace and were returned to France (Mashberg Reference Mashberg2022). The decision to return the ingots to France came as a result of the ship being flagged to France and being located within French territorial waters. However, China placed a claim to the ingots, citing that they were part of Chinese cultural heritage as they had originated from China (Mashberg Reference Mashberg2022). This shows the contrast in access to objects from shipwrecks from a maritime zone sovereignty claim compared to a cultural heritage claim. UNCLOS and CPUCH include sections that focus on the duty to alert the flag State should an object originally belonging to that State be discovered and identified. This assumes that the coastal State is involved in activities taking place over a shipwreck; however, with the role of ROVs and AUVs in accessing deepwater environments, there is the potential for the flag State to be the primary authority of the research expedition over sunken warships, with participation from other States. This leads to a question concerning the interaction and the duty of the flag State to alert the coastal State over data and objects discovered on warships.

11.5.1 Sovereign Immunity of Sunken Warships

The final element to discuss concerning the interaction of UNCLOS, CPUCH, and advancements in underwater archaeology focuses on the role of the sovereign immunity of sunken warships. As previously discussed, warships constitute a large number of recently discovered shipwrecks. Compared to other vessels used for commercial purposes, warships can have distinct legal protections (Dromgoole Reference Dromgoole2013). One of these distinctions is the sovereign immunity of the flag State over warships, which would be applicable irrespective of the maritime zone in which a warship was discovered.

Archaeologists are able to identify the original flag State of a sunken vessel based on access to historical logs, photographic evidence, and scientific testing to discover the State of origin. Through the use of photogrammetry, side-scan sonar, and other techniques, practitioners are able to gain clearer data to aid in the identification of sunken vessels. However, certain vessels may be difficult to identify based on environmental factors and the condition of the vessel. Scholars have mentioned the possibility of private salvage claims in instances where a ship is no longer able to be identified, and no flag State can be appropriately notified.

There is the potential for flag State jurisdiction over shipwrecks that have been successfully identified as warships under the principle of sovereign immunity. Scholarly discussions have considered whether sunken warships apply under the role of sovereign immunity, since they are no longer operating under the command of a captain or a crew and are incapable of navigation (Oyama Reference Oyaman.d.). This position stems from Article 29 of UNCLOS, which centers on the definition of warships:

The argument that sovereign immunity does not apply to sunken warships highlights the fact that sunken warships are not under the command of an officer or crew. However, State practice has shown that States often consider their sunken warships to be under their jurisdiction through sovereign immunity and their designation as war graves (Ronzitti Reference Ronzitti2011). There are scholars who support the view of sunken warships as being under the sovereign immunity of the flag State until the flag State has explicitly renounced its jurisdiction over the vessel (Ronzitti Reference Ronzitti2011). The application of sovereign immunity could place a right of access to the flag State, although it is likely that the coastal State would need to provide its consent if the shipwreck were located within its territorial sea, contiguous zone, or EEZ (Dromgoole Reference Dromgoole2013).

The coastal State is mentioned in Articles 149 and 303 of UNCLOS as having sovereign rights over objects of an archaeological and historical nature found within its waters. The CPUCH similarly gives rights of access to the coastal State. It then becomes important to consider the interaction between the coastal State and the flag State in cases that involve sunken warships if both have certain competing rights of access.

States have been able to manage shipwrecks effectively through bilateral agreements – as seen in the case of the HMAS Perth, an Australian warship located off the coast of Indonesia, by creating a conservation zone over the warship (Pearson Reference Pearson2023). Bilateral agreements between flag States and coastal States to create joint management plans over historic wrecks have been an effective measure and may be beneficial moving forward, as States continue to collaborate to conduct scientific studies of shipwrecks. The creation of a preservation zone surrounding US warships found off the coast of France has also been effective in preventing further damage (Mirasola Reference Mirasola2016).

11.5.2 Shipwrecks as Gravesites

Aside from the application of sovereign immunity, sunken warships and vessels may also simultaneously be gravesites. Increased access to shipwrecks means that there can be additional instances of disturbances that can interact with ethical concerns over shipwrecks as gravesites. It may be clear to acknowledge shipwrecks as gravesites considering those who perished with the ship; however, in practice, it can be difficult to enforce the idea of a sunken vessel as a gravesite without tangible evidence (Forrest Reference Forrest2003). Wrecks that have been submerged for years experience changes due to the environment, which may make it more difficult to identify exact objects or human remains. The use of robotic technologies and advanced imaging mechanisms can aid in capturing and verifying objects of an archaeological nature on the seabed without the need for retrieval. Without coastal State monitoring and patrol programs, it becomes difficult to enforce the management of underwater shipwrecks as gravesites to avoid disruption from commercial divers, tourism, and other actors.

Effective cases of the protection of shipwrecks as gravesites from unauthorized excavation use several types of mechanisms to surveil the area surrounding the shipwreck. This can be more imperative when it concerns wrecks that could cause damage to the surrounding environment if they are disturbed. The UNCLOS does not make direct reference to shipwrecks as potential gravesites, although Article 2(9) of CPUCH provides that States “shall ensure that proper respect is given to all human remains located in maritime waters.” Scholars have noted the discussion over the respectful treatment of shipwrecks as gravesites as a complex and challenging area (Delgado and Varmer Reference Delgado, Varmer, Guérin, da Silva and Simonds2014). The designation of a shipwreck as a protected gravesite can potentially impact further studies of the surrounding area and likely requires consent and collaboration between the various States involved. The definition of respectful treatment of shipwrecks is important, as technological advancements balance between assisting in uncovering data and not causing disruption to the site. An example is the expanding use of environmental DNA testing, which has been employed on skeletal remains discovered within the Antikythera shipwreck (Lewis Reference Lewis2016). The results of the environmental DNA testing can reveal aspects of the lives of sailors at the time of the sinking, as well as additional details about the State of origin (Briggs Reference Briggs2020). The Antikythera shipwreck involved a Greek vessel that was located within Greek waters off the coast of Crete (Theodoulou Reference Theodoulou and Sarris2015). This lessened the number of States involved in the management and ownership of the vessel, since it was discovered within the territorial sea of the original flag State.

Meanwhile, the management of sunken shipwrecks within the EEZ of a separate State can affect a number of decisions stemming from the ownership of the sunken vessel. For example, a State may decide to take action against a shipwreck that is considered a potentially polluting wreck, as well as making decisions concerning the removal of artifacts or other materials on board. Without clear ownership over a shipwreck, it can be hard to determine the correct authority to enforce actions that impact the wreck site, the surrounding marine environment, and the cultural connection to local inhabitants. It can be a timely process, involving national policies, to consider the wreck of a warship as protected within a foreign State’s EEZ, although this has been successfully negotiated through the wrecks of the HMCS Guysborough and the HMCS Athabaskan – Canadian warships located within the French EEZ (House of Commons, Canada 2018).

While UNCLOS and CPUCH are significant in deciding the role of flag States and coastal States regarding archaeological objects, there is a noticeable gap in the enforcement of protected shipwrecks as gravesites. Domestic legislation assists in filling these gaps with regard to shipwrecks flagged to the original State in whose waters they were located. This leaves a question concerning the ownership and enforcement of certain policies over wrecks outside of the national waters of their flag State. Several national policies surround State action over shipwrecks; these vary across States with distinct maritime histories, resources, and objectives. Examples of domestic policies concerning shipwrecks in foreign or international waters include the Abandoned Shipwreck Act of 1987 and the Sunken Military Craft Act of 2004 in the US, and the Protection of Military Remains Act 1986 in the UK (National Park Service 2023).

While regulations vary by country, most States that are heavily involved in archaeological research also have strict application processes and permits necessary for projects to move forward. Some States encourage the participation of a government official on board the archaeological research vessel to ensure that it is conducted according to plan. Other States, such as those that did not have active vessels at the time of the First and Second World Wars, may not have such an interest in accessing and studying foreign vessels. There have been cases where third parties, such as those outside of the flag State and the coastal State, have been involved in the disruption of wreck sites without the prior consent of the flag State or the coastal State. In these instances, it is important to consider how neither State was made aware of those activities until after the artifacts were taken and in transit, as is the case of the HMAS Perth (Hosty Reference Hosty2022).

Shipwrecks can also be potentially exposed to access by divers within the territorial sea. There have been cases of commercial divers excavating wreckage sites following the successful discovery of shipwrecks within different areas of the ocean, as seen in the case of the HMS Repulse and the HMS Prince of Wales (Grammaticas Reference Grammaticas2023). Shipwrecks are often exploited for their metal and other parts without regard to their applicability as marine conservation zones or gravesites. This can cause tension between the flag State of the vessel that has been excavated and the coastal State in whose waters the operations took place. Meanwhile, in instances where flag States and coastal States are working collaboratively toward the protection of a shipwreck, this can be derailed by actions taken by private companies contrary to the goal of protecting underwater cultural heritage. It is then difficult to consider the applicability of UNCLOS or CPUCH in safeguarding sites of archaeological importance from unauthorized excavation.

A case of competing interests over a shipwreck and its artifacts can be seen in the shipwrecks found by Enigma Recoveries off the coast of Cyprus and Lebanon. Enigma Recoveries used ROVs to excavate more than 588 artifacts from the wreck sites (Milmo Reference Milmo2016). These were then confiscated by officials from Cyprus, claiming that the wrecks were located within its waters. However, the private company claimed that the location of the wrecks is within the high seas between Cyprus and Lebanon (Maritime Executive 2020). The excavation was only possible due to the use of ROVs, and this sheds light on the importance of maritime boundaries when deciding ownership and access to shipwrecks. Along with technological advancements to study and preserve shipwrecks, there have been advancements that have led to a potential increase in tourism and commercial diving over shipwrecks. This is an area to consider for future research concerning legal access to shipwrecks in foreign waters by commercial divers and tourists (Ferentinos et al. Reference Ferentinos, Fakiris, Christodoulou, Geraga, Dimas, Georgiou, Kordella, Papatheodorou, Prevenios and Sotiropoulos2020).