If you are thinking of getting a turtle or tortoise as a pet you might want to avoid this lot because they are the largest and heaviest species of turtles and tortoises in the world! While they are not as big as other land and sea animals they are still pretty impressive… The Worlds Largest Species of Turtles and Tortoises 10 – Hawksbill Turtle – Average Weight: 68 KG – 150 Ib The hawksbill sea turtle is a critically endangered sea turtle belonging to the family Cheloniidae. It is the only extant species in the genus Eretmochelys. 9 – Flatback Turtle – Average Weight: 84 KG – 185 Ib The Australian flatback sea turtle is a sea turtle located