Local residents reported seeing the body offshore at around midday. Officers, along with forensic experts from Vachira Phuket Hospital, soon arrived at the scene.
Police soon identified the deceased as Thanyawit Thahanthai.
According to initial reports, Mr Thanyawit had been staying on the boat with the boat captain and a mechanic the night before. The crew had dinner together before retiring separately.
The following morning, the captain noticed Mr Thanyawit was missing while preparing to clean the boat. Before he could report the disappearance, authorities were informed that a body had been found, police noted in their report.
The body of Mr Thanyawit was discovered floating face down in the water, unclothed, with no visible injuries or signs of struggle. His relatives, who were traveling from Trang Province, have been notified, police said.
A preliminary examination conducted by forensic experts found no signs of foul play. However, the body has been taken to Vachira Phuket Hospital for a detailed post-mortem examination to determine the exact cause of death.