The body of 44-year-old Paul Vigay was discovered in the sea at Eastney on Friday morning.
Police said Mr Vigay, of Manners Road, Southsea, had been reported missing at 11pm on Thursday night.
The body was discovered by a member of the public w
ho was out on the beach walking their dog.
Police were called at 8.10am yesterday to the seafront next to the Royal Marines Museum, in Eastney where the body was found 10 metres from the shoreline.
Police cordoned off the area. Police say Mr Vigay's death is not being treated as suspicious.
A Hampshire police spokeswoman said: 'We were called by a member of the public after they saw the body in the water.
'The police, with the help of the coastguard, brought him in.'
She added: 'Investigations are under way.'
The Portsmouth Coastguard Rescue Team and an inshore lifeboat were on the scene assisting the police.
Local residents said they were shocked to hear about what happened in an area that is usually very quiet.
Charlotte Durkin, 20, of Esplanade Gardens, said: 'The sirens woke me up at about 8.20 this morning. I opened the curtains and saw police cars and ambulances. Nothing like that happens around here, it's a very quiet area.'
One resident from Esplanade Gardens, who did not want to be named, said: 'It's very quiet around here, it's very unusual to see so many police. But I don't know anything about what happened. The area is very busy with dog walkers. It's very sad, obviously.'
Another resident added: 'I have no idea what has happened. I heard a police siren and I looked out the window and saw the police cars. It was a bit of a surprise - and it's not a nice surprise. I know the police interviewed a couple of dog walkers.'
Undertakers were called to take the body away and a post mortem examination will be carried out to try to establish the circumstances which led to Mr Vigay's death.
Anyone with information should contact Portsmouth Police on 0845 045 4545 or 01962 841534, or Crimestoppers anonymously on 0800 555 111.
