The body was spotted near Rochester Pier in Kent early Monday afternoon, This is Kent reported.
Josh Thomas, 18, was stationed at Brompton Barracks in Chatham. He had been missing since April 10 and was last seen outside a Rochester pub, the City Wall.
On his last night, Thomas was celebrating passing the City & Guild Electrical Exam. Police said there was no reason to suspect foul play.
Thomas was from Swansea, Wales.