The man, Gong Yu*, 40, from Liaoning, China, was pulled from the water at about 4:20pm, confirmed Rawai Mayor Aroon Solos.
Mr Gong had entered the water to play with his son, Mayor Aroon told The Phuket News.
“He was in the water in a red flag ‘No Swimming’ zone. The son was brought safely back to shore but by the time lifeguards got back to Mr Gong he was already unconscious, he said.
Lifeguards performed CPR on the beach, Mayor Aroon explained.
An eyewitness to the incident provided a video to The Phuket News showing the lifeguards working frantically to try to revive Mr Gong, but to no avail.
“Mr Gong was then rushed to Chalong Hospital, where he was pronounced dead,” Mayor Aroon added.
* Correction: Mr Gong Yu, not Mr Yu Gong as initially reported. The error is sincerely regretted.