Sea turtles have several natural predators; these vary depending upon the sea turtle’s life stage.
Racoons, foxes, coyotes, feral dogs, ants, crabs, armadillos and mongooses can unearth and eat sea turtle eggs before they have the chance to hatch; crabs and birds can eat hatchlings as they run from the nest to the ocean, and fish (including sharks) and dolphins can eat hatchlings as they move from coastal waters towards the open ocean.
Although sea turtles have fewer predators as they increase in size, sharks and killer whales can predate adult sea turtles in-water, and jaguars and crocodiles have been known to predate adult female sea turtles as they climb ashore to nest.
References:
Heithaus, M.R. 2013. 10 Predators, Prey, and the Ecological Roles of Sea Turtles. The Biology of Sea Turtles, 3, 249. Heithaus, M.R, Wirsing, A.J, Thomson, J.A. and Burkholder, D.A. 2008. A review of lethal and non-lethal effects of predators on adult marine turtles. Journal of Experimental Marine Biology and Ecology, 356(1-2), 43-51.