Callum Jones, 20, broke his neck when he tripped on a submerged rock as he ran into the sea. He has undergone a gruelling eight-hour operation to rebuild the broken bone in his spine but his family say a miracle is needed if he is to walk again.
Callum, who is a keen cricketer and footballer, was rushed from the beach to A&E where scans confirmed he had fractured vertebrae in his neck. He was then airlifted to the University Hospital of Wales, Cardiff, where he remains in a serious condition in an induced coma.
His family fear he'll never be able to play football or cricket again, reports Wales Online.
Katie Jones, a family friend, said: "His life has changed in the blink of an eye. We are praying for a miracle. They are going to need all the help they can in the future.
"They are such a close family and they are devastated, as is everyone who knows Callum."
The freak accident happened to Callum after a cricket training session with his team Pembroke Dock on Thursday, July 22.
Katie added: "The boys noticed he was laying face down in the water and floating, and not responding.
"One of the younger boys went over and turned him over and Callum said 'help me'. He'd cracked his neck on an underwater rock and couldn't move."
Callum had a section of his hip bone removed in the eight-hour operation in an attempt to rebuild his damaged vertebrae but the accident has damaged his spinal cord and he has no movement from the neck down. He is due to have a tracheotomy on Friday and "that will be it," said Katie.
He is using blinking to communicate with doctors and his family, who are only able to see him twice a week.
Katie, from Kilgetty, south Wales, said Callum is the "golden boy" in his family and the eldest sibling of four.
His mum Joanna is especially concerned about the future and how to adapt her life for Callum's needs once he comes home.
Katie has set up a fundraiser for the family, which has so far exceeded ￡7,000.
To contribute to the fundraising visit https://uk.gofundme.com/f/a-little-help-for-callum-jones.