The man was identified as Brian Anning, 72, from Bognor Regis in West Sussex.
Mr Anning’s daughter, Ms Janet Stroud, told police that she and her father arrived on Phuket on Tuesday (Apr 12) and were set to depart on April 26.
“Ms Stroud said they came back to hotel together, and Mr Anning went swimming in the pool at about 6:20pm,” said Capt Chatree Chuwichien of the Karon Police.
Ms Stroud said she returned to the pool to find her father floating in the water.
“She called for hotel staff to help pull him out of the pool, but he was unconscious, not breathing and unresponsive,” Capt Chatree said.
Emergency services were called, but were unable to revive Mr Anning, who was pronounced dead on arrival at Vachira Phuket Hospital.
“The pool is only 1.5 meters deep,” Capt Chatree said. “There were no signs of a struggle on Mr Anning’s body, and we believe he died about an hour before we arrived.”
Ms Stroud said that her father had several health conditions, including diabetes, hypertension and heart complications, he added.
“Apparently he had been using insulin for a long time,” Capt Chatree said.
“He may have suffered a diabetic shock while in the pool, which may have caused or contributed to his death,” Capt Chatree suggested.
“We are waiting for doctors to conclude their appraisal and determine the actual cause of death.”