The U.S. Coast Guard rescued the man, identified as Jerry Whipple, on Wednesday afternoon.
Coast Guard Petty Officer First Class Mariana O'Leary says they suspect the man was very drunk.
The Coast Guard says a boater reported seeing an unconscious man floating well offshore. The Coast Guard and a Clearwater Fire Rescue unit responded and found the man, still unconscious and wearing a life jacket.
He eventually woke up and was checked by paramedics at a Coast Guard station.
O'Leary said the Pinellas County Sheriff's Office will investigate the incident.