Officials say 39-year-old Maj. Jeffery Vincent was on leave in Florida when he disappeared on Sunday. He was on a scuba diving trip with his friends off the coast of Key Biscayne.
Police say he jumped into the water, missed the safety line off the back of the boat, and was swept away.
The Coast Guard says Vincent was wearing all of his diving equipment, except his fins.
Vincent is a reservist from the 9th Space Operations Squadron.