Pol Capt Wisanu Chalok, deputy investigation chief at Tha Sala, said the discovery at Bonon beach was reported around 6.30am.
Police found no identification documents on the dead man, who was estimated to be between 35-40 years of age.
The body was dressed in purple fisherman’s pants. There were no visible bruises. A doctor estimated the man had been dead for at least one week before his body was found.
Police said it was likely he was an illegal migrant working on a fishing vessel.He might have fallen over board or even been murdered. There was no obvious evidence. His head could have been taken by a sea creature.
Police were attempting to identify the man and the circumstances of his death