The 'irresponsible actions' of 'tombstoners' have again caused problems for the coastguards rescue agencies and ambulance crews following two separate incidents in the county.
In the first incident, a 12-year-old Fishguard boy was injured as he jumped from the harbour wall at Lower Town, Fishguard, at approximately 8.30 pm on Friday.
The sextet were tombstoning into the sea at the far end of Lydstep Beach, near to the Blow Holes, when the incident occurred at approximately 5.35 pm on Saturday.
The youths were leaping approximately 30 feet from a ledge into the sea, but the pursuit nearly ended in tragedy when one participant hit an obstruction while jumping and severely injured his leg.
He managed to get out of the sea onto a lower ledge, but when the coastguard rescue teams from Tenby and Manorbier arrived, they found that it was impossible to retrieve the youth by using the usual cliff rescue methods.
As a result, Tenby's RNLI inshore lifeboat was launched, and a rescue helicopter from RAF Chivenor was summoned.
On their arrival, the lifeboat made contact with the injured young man, while the winchman from the helicopter was lowered down to attend to him. The ILB crew assisted the winchman in stabilising the casualty and after stabilising his injuries, he was winched aboard the helicopter and taken to Withybush Hospital, Haverfordwest, with a suspected broken leg and spinal injuries.
The incidents have led to coastguard officials issuing a warning about the dangerous consequences of this latest craze.
"Both parties did not have any idea of the dangers of this 'alleged good sport' and all risked their own lives and the lives of those who went, in particular at Lydstep, to their rescue," said Angie Smith, DPRO, Milford Haven Coastguard.
"It is foolhardy to play this game and coastguards and other rescue authorities condemn the actions of all those who participate," she added. A warning has also been issued by the RNLI.
Steve Wills, RNLI beach safety manager said: "RNLI volunteer lifeboat crews risk their lives to save others in dangerous situations at sea and we're becoming increasingly concerned about the number of tragic tombstoning incidents that are happening needlessly around the coast that we, and other rescue organisations, are being called to deal with. "Our advice applies to everyone - young, old, male and female - don't do it. Jumping from a height into water can kill. I urge people to think of the consequences of their actions.
"Young adults and teenagers can be easily impressionable and there have been reports of websites displaying tombstoning videos and incidents involving older men jumping into the sea - I'm concerned that young people may try to copy what they see.
"This year so far there have been at least five deaths that we know of from tombstoning, and many more call-outs by RNLI crews and lifeguards."