Tourist Police were notified of the incident at 3:30pm.
Officers identified the Frenchman as Joel Dreux, age 56.
Mr Druex went on a trip to Mu Ko Surin National Park with his wife on a tour booked through Siam Adventure Tours, explained the tour guide for the trip, Weerawut Nukulwan, 25, in his statement to the Tourist Assistance Centre (TAC) in Phang Nga.
Mr Dreux went snorkelling at 2pm, at the last point of the trip, Mr Weerawut explained.
Mr Dreux was seen choking on water and was pulled back onto the boat.
“He was weak but could still speak,” Benjamas Khumtup of the Phang Nga TAC explained to The Phuket News today.
However, Mr Dreux fell unconscious and staff on the boat were unable to detect a pulse, and began performing CPR, Mr Weerawut noted in his statement.
“After that we contacted National Park officials who took a rescue boat with a team of military doctors from the Navy to assist and transferred him to Khura Buri Chai Phat Hospital in Phang Nga,” the tour guide explained.
At the hospital, doctors helped to continue performing CPR, but Mr Dreux was later pronounced dead, he said.
The cause of death was given as drowning, the Phang Nga TAC confirmed.
Mr Dreux’s body remains at the hospital while arrangements are made to repatriate his remains home, the TAC confirmed.