The dead man, named by police as Martin-Anders Christer Nilsson, was staying with four family members on the island, and went out fishing this morning, alone in a dinghy.
The empty dinghy was later noticed from the shore. A boat was sent out to check and Mr Nilsson's body was found floating close by.
The body was brought back to Chalong and was then taken to Vachira Phuket Hospital where an autopsy will be performed to establish the cause of his death.