The 76-year-old was airlifted to hospital after being found in the water at the East Sands area in St Andrews on Monday evening.
He was later pronounced dead at Ninewells Hospital in Dundee.
Police Scotland said his death was being treated as unexplained, but was not suspicious. A report has been submitted to the procurator fiscal.
The man, who police did not name, was spotted in the water by a member of the public about 8:25pm on Monday.
A beach towel, clothing and sunglasses were recovered from the shore.