The Mason County Medical Examiner identified the victim as Kyle Austin Pape of Fox Island, Washington.
Witnesses called 911 just before 5 p.m. to report Pape dove into the lake but didn't surface. Others swimming with Pape searched the area and found no sign of him.
A dive team was called in and found Pape under water, unconscious just after 6:30 p.m. Medics tried to resuscitate Pape but were unsuccessful and Pape was pronounced dead a short tiem later.
An autopsy is scheduled for Tuesday, and the Mason County Sheriff is investigating.