Marine Corps spokesman Lt. Justin Smith said Saturday that Sgt. Wesley J. Rice was unable to get out of the vehicle when it sank. He was one three instructors in the vehicle along with three trainees.
The five others aboard escaped safely.
Rice was declared dead at a hospital Friday about three hours after the LVT-7 Amphibious Assault Vehicle sank in the Del Mar Boat Basin in Oceanside Harbor.
Rice served two tours in Iraq and won several awards including a Combat Action Ribbon.
The Marine Corps said the accident was under investigation and the cause remained unknown.
