Two more bodies have been found on the beach at Camber Sands, East Sussex, where three men died after being pulled from the sea earlier on Wednesday, the RNLI said.
The bodies were discovered at around 8pm by a member of the public as the tide receded.
A search is under way for a further missing person, with two lifeboats and a helicopter combing the water off the coast.
Richard Tollett, lifeboat operations manager at Rye Harbour, told the Press Association the RNLI received a request to launch at around 8.30pm.
He said: "As the tide has receded it has left a couple more bodies on the beach in the sand at Camber.
"A member of the public found them and that person reported another one in the water so we have got two lifeboats and a helicopter searching the area trying to find the other one."
The genders of the two bodies recovered on Wednesday evening have not yet been established, he added.
The first three men died despite efforts by medics to save them after being pulled from the sea near Rye at about 2.15pm.
Suggestions that the deaths may be linked to jellyfish have been ruled out, and Sussex Police said there was nothing to suggest the men were migrants.
The five who perished at Camber Sands bring the death toll around Britain's coastline to 12 over the last week, prompting calls from the RNLI to urge seaside visitors to take care and respect the water.