Lt Col Jarat Lempan, Deputy Chief Inspector of Chalong Police, was called to the beach at 7am.
Boonsom Phonrob, headman of Moo 1, Rawai, reported the body after a local fisherman spotted it in the water among rocks in front of the Windmill Viewpoint, just north of Yanui Beach.
Vachira Phuket Hospital medical staff and Kusoldharm Foundation rescue workers were called to the scene. Also soon to arrive was Chalong Police Chief Col Ekarat Plaidueng.
Rescue workers took several hours to safely recover the body, which was in an advanced stage of decomposition, from where it was lodged among rocks on the coastline.
The body was finally carried ashore by lifeguards at 9:50am.
The body was dressed in a round-necked shirt with green stripes with a Heineken beer logo as well as black underwear and green shorts. A red Converse shoe was still on one foot.
A red waist bag was still on the body, containing an American passport and a variety of currencies including Thai baht, US dollars and Korean won, together totaling more than B30,000 in value.
Officers also found a ‘Alien Registration Card’ issued by South Korea identifying the man, originally from Pennsylvania.
Officers also found a key card for a room at Naiharn On The Rock resort.
Police at this stage postulated that the man had fallen from the rocks into the water, and that he had died at least seven days before his body was found.
Chalong Police are checking CCTV in the area and have confirmed that the man was last seen at the hotel on July 7.
Officers are continuing their investigation.
The body has been taken to Vachira Phuket Hospital for post-mortem examination in the hope of confirming the cause of death.
The US Embassy in Bangkok has been notified of the man’s death, police confirmed.