​The ocean is home to many marine animals which embark upon migrations, connecting different parts of the ocean. These migration pathways do not recognise human-made boundaries and often include both coastal and oceanic habitats. These case studies use data from Migratory Connectivity in the Ocean (MiCO) to show the journeys of three highly migratory marine species. Leatherback turtles (Dermochelys coriacea) are highly mobile species that migrate across entire ocean basins. Pacific leatherbacks form two distinct breeding population groups with different migration patterns (Bailey et al. 2012). In the eastern Pacific, nesting populations are found along the coasts of Central America, while western Pacific populations nest primarily in the Solomon Islands, Papua New Guinea, and Papua Barat, Indonesia (Dutton et al. 1999, 2007). Historically, both populations have been robust, but because of their long migrations and relatively long life cycle, they are highly sensitive to several anthropogenic stressors. These populations are currently in decline and listed as “critically endangered” on the International Union for Conservation of Nature (IUCN) Redlist (Tiwari et al. 2013). Understanding the political biogeography of these highly threatened populations is especially important, as their management is jurisdictionally complex.