The turtle, found by a group of people on Vinh Hy Beach in the Nui Chua National Park, weighed 20 kilograms and had a 40cm-wide shell with brown patterns.
"Maybe it was caught in a net and its limbs got cut off," a local said.
The carcass was later buried by locals.
The creature was a green sea turtle, Nguyen Tuong Giao, deputy director of the park, said.
The species faces extinction from hunting, poaching, egg harvesting, and unintentional threats like boat strikes, fishermen's nets that lack turtle excluder devices, pollution, and habitat destruction.
The species is classified as endangered by the International Union for Conservation of Nature, and it is illegal to either collect, harm or kill them.
Five turtle species are listed in Vietnam’s Red Book: the green, hawksbill, loggerhead, leatherback, and olive ridley. Hunting or trading of any of them is a crime.