A 23-year-old man has been pulled unconscious from the sea after jumping off a cliff into the water, police say.
Dyfed-Powys Police urged people not to take part in "tombstoning" following the rescue in Tenby, Pembrokeshire, on Saturday evening.
It said it was called to the beach opposite St Catherine's Island at about 18:15 BST.
The man was not breathing but was given CPR and regained consciousness, it said.
Insp Gavin Howells said: "This incident highlights the serious danger posed by tombstoning or cliff jumping, and the potentially life-threatening consequences.
"We urge people not to take part in this sort of activity anywhere along our coastline, and not to put themselves or the emergency services at risk for a thrill."
He thanked the RNLI for their swift response, adding their actions "most likely saved this man's life".
Tenby RNLI said its inshore lifeboat was launched and when its volunteer crew arrived the man had been pulled from the water and was on the rocks.
The coastguard said it also attended and the man was taken to Morriston Hospital in Swansea by road ambulance.