Saint-Pierre and Miquelon is a French self-governing overseas territory near the Canadian province of Newfoundland and Labrador. Seven diadromous species occur in the rivers and ponds of this archipelago: Anguilla rostrata (Lesueur, 1817), Osmerus mordax (Mitchill, 1814), Salmo salar Linnaeus, 1758, Salvelinus fontinalis (Mitchill, 1814), Apeltes quadracus (Mitchill, 1815), Gasterosteus aculeatus Linnaeus, 1758 and Pungitius pungitius (Linnaeus, 1758). For each species, we review nomenclature, give all arguments delineating the taxon according to an integrative approach (morphology, molecular, time divergence, cytogenetics, life traits histories, ecology, ethology, reproductive isolation), as well as their distribution in the archipelago and their IUCN status. We highlight taxonomical issues among O. mordax, S. salar and P. pungitius for which a taxonomical revision is needed. We consider the genus nomen Anguilla Thunberg, 1795 as not available according to the International Code of Zoological Nomenclature. Osmerus abbottii Cope, 1870 is now a junior synonym of O. mordax. We handled the invalidation of the names Salvelinus kingi, S. multidentatus and S. angustus which are junior synonym of S. fontinalis. Gasterosteus biaculeatus Mitchill, 1815 is not available. The type locality of Gasterosteus globiceps Sauvage, 1874 cannot be in North America but probably France, we thus agree to consider this nomen as a junior synonym of Pungitius laevis (Cuvier, 1819).