The dead whale was salvaged on Wednesday by Ao Siam National Park officials.
The carcass had been bleached white by the sun, indicating the giant mammal died about seven days ago.
"We towed the carcass to shore so that officials at the Marine and Coastal Resources Research and Development Centre can perform an autopsy," a park official said.
The Bryde's whale is a baleen whale or filter feeder. It belongs to the same group as humpback and blue whales.
Bryde's whales usually appear individually or in pairs, and occasionally in loose groups of up to 20 animals around feeding areas. They are the most frequently spotted among the 22 species of dolphins and whales that live in Thai waters.
The Bryde's whale is listed in Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals. It has an unfavourable conservation status and “would benefit significantly from international cooperation organised by tailored agreements”.