The passage of submarines through waters subject to coastal State sovereignty is the focus of this chapter. Coastal State sovereignty over its territorial waters is subject to the right of all ships, including submarines, to innocent passage. Submarine passage may not prejudice the peace, good order or security of the coastal State, it must be on the surface with flag flying, and adhere to requirements in place for navigational safety, potentially including any traffic separation schemes or routeing measures. For international straits subject to the regime of transit passage and in archipelagic sea lanes, submarines may stay submerged. The requirements associated with passage through international straits and archipelagic waters are examined in this chapter, including the parameters of coastal State rights to regulate these forms of passage and respond to potential violations of passage rights.

This chapter examines international obligations imposed on all States to protect and preserve the marine environment in relation to submarine operations. However, the sovereign immunity of military submarines significantly impacts both the applicability and enforcement of international marine environmental law. At present, nuclear powered and nuclear armed submarines pose the greatest environmental risks, and we discuss nuclear liability regimes, the possible relevance of nuclear-free zone treaties, and environmental obligations when decommissioning nuclear submarines. The obligation to prevent, reduce and control marine pollution may also be relevant in the context of sonar being used to detect submarines, as concerns have arisen as to the negative implication for marine mammals. While there have been various legal initiatives to address noise pollution, it is apparent that the consequences for military submarines is slight.

This chapter focuses on the different ways that strategic uses of submarines have influenced developments in international law. It highlights the security dimensions in discussions at the failed Second Law of the Sea Conference in 1960. Superpower dynamics during the Cold War also influenced decisions leading to the negotiations for the UN Convention on the Law of the Sea as well as the negotiations themselves. The growing importance of nuclear-powered submarines, as well as nuclear weapons on conventionally-powered submarines, spurred international agreements on nuclear non-proliferation and disarmament. This chapter brings to the fore the strategic importance of military submarines for major maritime powers in recent decades as it provides critical context for contemporary development and application of international law. We conclude Part I of the book in this chapter in bringing together key themes in the legal history of submarines that continue to influence the modern international law of submarines.

This chapter sets out the rationale for and provides an overview of the content of Submarines in International Law. It discusses a definition of submarines and describes a legal taxonomy of submarines; explaining how submarines may be categorized in a way that is legally relevant by considering the owner/operator, the purpose, their mode of power, and weaponry aboard. A critical consideration in addressing the international laws regulating submarine operations is the sovereign immunity that may apply and legal consequences of that immunity. Whether a submarine is nuclear powered or nuclear armed may also hold legal relevance. It is also important to acknowledge the growing private use of submarines for diverse reasons: criminal activity, research and for leisure. These uses are also regulated under international law and the chapter explains the different bodies of international law that are canvased in the book.

This chapter analyses submarines activities against requirements under the law on the use of force (jus ad bellum). Key actions at issue in this regard are the submerged passage of a foreign-flagged submarine in the territorial waters of a coastal State, as well as coastal State responses against a submerged submarine. We examine when submarine activities may constitute a prohibited threat of the use of force, as well as an unlawful use of force, in violation of Article 2(4) of the UN Charter. Military submarines may be deployed lawfully in response to an armed attack, provided the requirements of the right of self-defence are met. Submarines may also exercise a lawful right of unit self-defence where that response is necessary and proportionate. Responses of coastal States against submarine operations are also assessed within the law on the use of force.

In this chapter, we examine the allocation of rights and duties between States in relation to foreign-flagged submarine activities in the exclusive economic zone (EEZ) of a coastal State. Submarine activities include military activities and intelligence gathering, as well as extending to different forms of research. We assess the difference between military research and other forms of marine scientific research and the concomitant rights and duties of States in relation to these different types of research. Privately owned submarines may also engage in commercial activities in the EEZ associated with the exploration and exploitation of natural resources, the laying of submarine cables and pipelines, and for leisure or tourism purposes. The chapter identifies the applicable rights and responsibilities under international law to regulate those activities, as well as explaining limits on the rights of States through reference to due regard and non-abuse of rights.

In this chapter, early efforts at legal codification relevant to submarines are seen in the work of learned societies, such as the Institut de Droit International and the International Law Association, as well as in discussions leading to the conventions adopted at the two Hague Peace Conferences. However, submarines were not specifically addressed but fell within a category of belligerent warships; an early proposal to ban submarines as weapons being unsuccessful. Discussions at this time concerned passage in territorial waters and straits, and particularly the rights and duties of belligerents and neutrals. International law on navigational rights in territorial waters was unsettled as World War I began. The critical role of submarines during World War I prompted States to adopt laws that specifically addressed submarines, including requirements to surface in the territorial sea. The chapter reflects on these emergent laws regulating submarines in both times of war and peace.

In this chapter, we assess the international law regulation of the newest forms of submarines, underwater maritime autonomous vehicles (UMAVs) and ask what changes for States’ rights and duties when an autonomous vehicle operates uncrewed and underwater. A core issue has been whether UMAVs are ships or not and we address differences emerging for floats and gliders particularly. Whether uncrewed submarines are ships or not has implications for navigational rights and duties. We also consider questions emerging under the law of armed conflict and distinctions for autonomous maritime systems (such as mines and torpedos). While State-owned and operated UMAVs are a primary focus, we also consider the international laws applying to the use of UMAVs by terrorists or criminals seeking to smuggle goods. This chapter concludes Part II of the book and brings together the key questions that remain to be answered in regulating submarines in international law.

This chapter examines legal developments in submarine regulation taking into account the political context existing prior to World War II, including tensions in the Pacific with Japan’s aggression against China. Notably, States adopted the 1936 London Protocol on Submarine Warfare seeking to align requirements for submarines with obligations imposed on surface warships. Tensions in the 1930s also prompted Turkey to initiate a revision of the legal regime governing the Turkish Straits, leading to the Montreux Convention and the near complete prohibition of submarine passage in these waters. With the outbreak of World War II and unrestricted submarine warfare, questions emerged as to the viability of rules set out in the 1936 London Protocol. States also moved to revise laws of neutrality with more targeted consideration of submarines. The chapter thus reflects ongoing legal developments concerning navigational rights of submarines in territorial waters and the regulation of submarines during armed conflict.

In assessing international law governing submarine warfare, we consider how peacetime rules from the law of the sea apply in an armed conflict and focus on the law of neutrality and the law of armed conflict (international humanitarian law). The allocation of rights and duties within different maritime zones continues, albeit with some modifications, during an armed conflict. Most notably, the law of neutrality establishes how those rights and duties change depending on a State’s status as a belligerent or neutral. The use of submarines during armed conflict is also governed by the law of naval warfare and they are largely subject to the same rules that restrict surface warships in relation to targeting, as well as the means and methods of warfare. While submarines are predominantly governed as warships, we note how operational limitations of submarines may affect the interpretation of some rules.

This chapter draws out international laws applicable to ensure the navigational safety of submarines and to establish what laws apply when a submarine is ultimately lost at sea. The discussion is concerned with both military and private submarines during times of peace. To avoid collisions, submarines must account for surface traffic as well as submerged traffic and deploy appropriate signals and sounds. Submarines prompt distinct questions with regards to navigational safety. Where a submarine is in distress and ultimately sinks, consideration is further needed as to international law rules on search and rescue, as well as the law of wrecks and possible salvage. For submarines that have been lost at sea for a long time, safeguarding underwater cultural heritage may become a key consideration. When lost at sea, the relevant laws are comparable to other ships or warships but the difficulty rests in the interaction of those rules.

The use of submarines in World War II and the development of submarine technology into the Cold War had implications for different fields of international law. This chapter addresses the peace negotiations and agreements that were adopted after World War II, which concerned the decommissioning (to varying degrees) of submarines and efforts to revise the Montreux Treaty. International law developments were sometimes slow, as evident in responses to violations of the law of naval warfare. Equally, the chapter highlights the rise of nuclear technology in relation to submarines and the modest advances in international agreements on nuclear tests. Despite the growing strategic importance of submarines in the Cold War, their explicit regulation in the 1958 conference and treaties on the law of the sea was scant. Instead, international laws relating to the passage of warships and military activities on the high seas generally impacted international laws regulating submarine operations.