Coastguards have issued a warning after a boat accompanying a swimmer across a Carmarthenshire estuary broke down and the swimmer disappeared.
A search involving the police and rescue helicopters helicopter was launched after the vessel made a mayday call at 1820 BST on Sunday.
The swimmer was found about 40 minutes later by Burry Port lifeboat.
Coastguards said breakdowns at sea can be serious and boat users should make checks before leaving shore.
The may day call from the vessel the Lady May on Sunday evening was heard by another boat Liberty and relayed to the coastguard.
In the call the Lady May reported it had broken down and was caught in heavy swell between Whiteford Lighthouse and Whiteford Point.
Swansea Coastguard co-ordinated the rescue and when the Liberty arrived at the scene it reported the boat was escorting a swimmer who had disappeared from view.
The search was escalated and Burry Port RNLI inshore lifeboat, Tenby RNLI all weather lifeboat and an RAF rescue helicopter from Chivenor in Devonwere sent to the scene.
Dyfed-Powys police helicopter and the Liberty also joined the search.
Burry Port coastguard rescue team were also sent to set up the helicopter landing site, but the swimmer was found just before 1900 BST.
The swimmer did not need medical attention and was taken back to the slipway at Burry Port.
Swansea Coastguard Watch Officer Bernie Kemble said: "Breakdowns at sea can have serious consequences so please make sure you're engine is well maintained and that all the shore side checks have been carried out before you leave your moorings.
"When Burry Port lifeboat found the swimmer they were being swept away from shore and had been in the water quite a while.
"Before you jump attempt a swim please consider that swimming in the sea is more exhausting than swimming in a pool and tides can carry you away from your destination so know your limits and don't forget to check the tide."