A statement says Chief Warrant Officer Jose Eduardo Lopez Cobena died Thursday. Details about the incident were not immediately released.
The 40-year-old Lopez was based at Fort Carson, Colorado, and was on a 12-month assignment to Guantanamo that began in June. He had a nearly 20-year career in the military and had received many commendations including a Bronze Star. Lopez was originally from New York.
Guantanamo is perched at the edge of the Caribbean sea in southeast Cuba and the water surrounding the base can at times be treacherous. Three Marines drowned in an incident in July 2010.