The oldest sea turtle is said to be 400 years old. It is in captivity in the Guangzhou Aquarium in China and weighs 300 kilograms. It is not possible, however, to determine the age of the oldest sea turtle in the wild.
Most sea turtles, especially the males, almost never leave the ocean, which makes it more difficult to keep track of their population and ages. The largest and oldest known sea turtle species is the leatherback turtle, which is believed to have existed for more than 150 million years. Leatherback turtles also have a longer lifespan compared to other turtles and can live up to 100 years.