Crews said they responded to a report of an unresponsive man in the water in Westport Saturday afternoon.
The incident happened at approximately 1:35 p.m. in the waters off of Cockenoe Island.
Police said an unresponsive man was apparently suffering from some type of medical episode while swimming when they found him.
Crews said they responded to an alert on marine radio from private boaters in the area.
Marine officers were able to find the man, who was brought aboard a police boat, crews said.
Officers brought the man back to shore where he was transported to Norwalk Hospital for treatment.