Police were called to the North River Wednesday after they received a report about a man entering the water in his underwear.
R-C-M-P and Charlottetown City Police were alerted, as were the Coast Guard and the North River Fire Department.
The Coast Guard and the fire department sent boats into the water, but the man was later found in a nearby parking lot.
The man told police he is a marathon runner who cools off by plunging into the water after a long run.