Lott was taken in critical condition to Flagler Hospital, where he was pronounced dead, officials said.
St. Johns County Fire Rescue Lt. Lucas Smith said rip currents were a risk at the beach Sunday, Jacksonville media outlets reported. A red flag warning was in effect when Lott went missing.
Two other people died after an unrelated incident on St. Simons Island, The Atlanta Journal-Constitution previously reported.
MORE: Rescuer dies trying to save woman, toddler from drowning
Gregory Grant, 39, of Brunswick, went into the water Sunday to help a woman and a child who were struggling to get back to shore, Glynn County police said.
The woman, 34-year-old Aleisha Rankin of Jesup, and the toddler child made it back to land but Grant never resurfaced. Rankin later died at the hospital. Police said the toddler was in good condition.
About 7:30 a.m. Monday, family on St. Simons Island spotted Grant’s body in the water. He was pronounced dead at the scene.