Two anglers have died after their boat capsized in the sea near Burry Port off the Carmarthenshire coast.
The two men were pronounced dead at hospital
David Gwyn Richards, 60, and Paul Meredith, 36, were both from Swansea. A third man has been released from hospital after he was pulled to safety.
Coastguards said the emergency resulted in one of the biggest rescue operations in the area in recent times.
They were alerted by another boat in the Loughor Estuary which reported a man shouting for help in the sea.
The alert was first raised around 2030 BST on Tuesday.
Steve Jones, watch manager with Swansea Coastguard, said someone on the boat heard cries for help coming from the disused Whitford Point lighthouse area on the north Gower coast.
"We immediately asked him to proceed to the area when he actually pulled a person from the water who then told him their boat had sunk and two persons were missing," said Mr Jones.
"It's one of the biggest search and rescue operations off the Gower coast in recent times involving an RAF rescue helicopter, the Burry Port and Tenby lifeboats, independent lifeboats from Loughor and Ferryside and our own rescue teams from Loughor, Rhossili and Burry Port."
Coastguards took part in a large rescue operation
The missing anglers were found two-and-a-half hours after the first emergency call, he added.
They were brought ashore at Burry Port and pronounced dead at Glangwili Hospital in Carmarthen.
Dyfed-Powys Police have begun an investigation and are appealing for anyone who saw the boat capsize to come forward.
It is believed the boat which capsized was a 14ft angling boat.
The Marine Accident Investigation Branch has launched a preliminary investigation into the accident.