We present the first elucidated marine trematode life-cycle for southern Africa, involving intermediate and definitive hosts from the southwestern Indian Ocean, through southern South Africa and to the southeastern Atlantic Ocean in Namibia. Adults of Rhipidocotyle meridionalis n. sp. were found infecting leerfish, Lichia amia (L.) (Carangiformes: Carangidae), in the Tsitsikamma section of Garden Route National Park, South Africa. Bucephalid sporocysts and cercariae isolated from a brown mussel, Perna perna (L.) (Bivalvia: Mytilidae), were subsequently recovered from the same area and are a perfect genetic match with adults of R. meridionalis n. sp. based on the partial 28S rDNA region. Metacercariae encysted in multiple organs of the following fishes were found to genetically match this taxon: Chelon richardsonii (Smith) (Mugiliformes: Mugilidae), Dichistius capensis (Cuvier) (Centrarchiformes: Dichistiidae) and Diplodus capensis (Smith) (Eupercaria i. s.: Sparidae) from the coast between Swakopmund and Walvis Bay, Namibia; Chelon dumerili (Steindachner) (Mugiliformes: Mugilidae), Chrysoblephus laticeps (Valenciennes), Dip. capensis, Sarpa salpa (L.) and Sparodon durbanensis (Castelnau) (Eupercaria i. s.: Sparidae) from Tsitsikamma; Amblyrhynchote honckenii (Bloch) (Tetraodontiformes: Tetraodontidae) and Rhabdosargus holubi (Steindachner) (Eupercaria i. s.: Sparidae) from Witsand; A. honckenii from Chintsa, De Hoop Nature Reserve and Uvongo; and Dip. capensis from Mossel Bay. The southern coast of South Africa, where the type-locality of R. meridionalis n. sp. is located, is influenced by both cold Atlantic and warm Indian Ocean currents and is thus subjected to complex hydrological patterns. This life-cycle, linking hosts present in both oceans, informs both the picture of host- and trematode connectivity in southern Africa.