Pierson was 59, said Tybee Island Police Chief Bob Bryson. He had no known medical condtions.
Just before 11 a.m., Tybee police and emergency responders were alerted to a man struggling in the water off the beach between 12th and 13th streets, said Tybee Island Fire and Emergency Services Chief Skip Sasser. That beach is not protected by lifeguards.
Bystanders pulled Pierson from the water and Ocean Rescue performed CPR, Sasser said. He was transported to Memorial University Medical Center where he died.
Bryson said an autopsy would be performed within a few days and a toxicology test would also be administered. Results likely would not be available for one to three months.
Pierson was the first reported drowning death this year at Tybee Island.