Cmdr. Mark Evans of the Jacksonville Beach Police Department said the swimmer was taken to Baptist Beaches, but is in stable condition.
Red flags are up on packed beaches for the Memorial Day weekend, which warns swimmers about treacherous currents and rough seas.
"The recommendation is to stay out of the water," Evans said.
He said most people are adhering to the recommendation, but some aren't.
Jacksonville Beach lifeguard officials said they have been very busy and have pulled several people from the ocean during the holiday.
A spokesman said anyone that does get in the water should swim near a life guard station.
This story originally appeared on the Florida Times-Union.