Sea turtles (Superfamily Chelonioidea) are turtles found in all the world's oceans except the Arctic Ocean. There are seven living species of sea turtles: flatback, green, hawksbill, Kemp's Ridley, leatherback, loggerhead and olive ridley. The East Pacific subpopulation of the green turtle has been classified as a separate species in the past as the black turtle. However, DNA evidence indicates that it is not evolutionarily distinct from the green turtle.

All but the leatherback are in the family Cheloniidae; the leatherback belongs to the family Dermochelyidae and is its only member.The Flatback turtle is found solely on the northern coast of Australia.