A missing 23-year-old Canadian national was found dead in the sea off Koh Chang in the eastern province of Trat on Sunday evening, tourist police reported.
Salih Kaled had booked into the Pajamas Hotel in tambon Koh Chang arriving on the island on Saturday and he was due to check out on Monday.
He went swimming at the beach in front of the hotel about 6 pm, police said.
Hotel staff suspected something may be wrong when he did not come back to shore, and reported his disappearance about 7pm.
A search by rescue volunteers, police and the navy found his body in the sea around 8.40pm.
His death was reported to the Canadian embassy. A post-mortem examination was under way.
Kaled arrived in Thailand on July 10 and was scheduled to leave the country on Aug 8, police said.