The York County coroner's office was called to the reported incident at Goldsboro Marina near North River Street near Three Mile Island at 6 p.m., authorities say.
Boaters spotted the man and attempted to rescue him, the release explains.
EMS was called but despite life-saving measures he was declared deceased at 5:57 p.m., according to the release.
His next of kin are being notified. An autopsy has been scheduled for Wednesday, June 1 at 10 a.m at Lehigh Valley Hospital.
Click here to follow Daily Voice Gettysburg and receive free news updates.