Donna Price, district administrator for Virginia's Office of the Chief Medical Examiner, wrote in an email Tuesday that the death was ruled an accident.
Petty Officer First Class Devon Grube was kayaking with a friend Wednesday when his vessel overturned near Cape Charles. The U.S. Coast Guard brought him ashore unconscious. He later died in a hospital.
According to the National Oceanic and Atmospheric Administration, the water temperature was about 45 degrees.
U.S. Navy Lt. Trevor Davids said last week that the Navy is conducting a full investigation. Grube was stationed with a Naval Special Warfare unit in Virginia Beach.