A Royal Marine is fighting for his life at Derriford Hospital in Plymouth after getting into difficulties while training on a beach in Cornwall.
The man, who is yet to be named, was pulled from the sea off Tregantle Beach near Plymouth on Tuesday 21 January.
It's thought he is a recruit and was in full kit at the time.
His next of kin have been informed.
A Royal Navy spokesperson said in a statement:
South Western Ambulance Service said it was alerted to an incident on Tregantle Beach at around 10pm on Tuesday evening.
A caller was told a person "had gone underwater". The service sent land, air and other specialist paramedics to the scene.
A spokesperson said: “They treated a male patient at the scene and he was conveyed by air ambulance for further care.”