The woman and man who died at Fistral Beach are said to be a father and his daughter, with the pair understood to have been on holiday in Cornwall.
The Sun reports that one witness – a local beach artist – claims the man had “gone in to try and rescue his daughter”.
Sand Phoenix, 33, said he “sprinted” up to help, jabbing the man with an adrenaline pen he had to hand and trying to give him oxygen.
His attempts to save the man’s life were in vain, however, as the victim’s lungs were “full of water”.
Mr Phoenix, who was sleeping on the beach at the time of the incident, said: “He had been pulled out of the water but had been in there about seven minutes.
“The paramedics arrived and carried on trying to give CPR. He was still wearing his trousers so I don’t think he had been swimming.
“It looks like they had been walking near the rocks and had fallen in.”
Another bystander explained he heard shouts for help and saw a woman lying face down in the water when he went down the cliff.
The brave man went into the sea fully clothed in an attempt to grab the woman, who was being bashed against rocks by waves.
Another witness told the Sun: “A woman was desperately trying to ring someone but couldn’t get through [and] was in tears.
“There was a helicopter overhead and there was a lifeboat in the water.
“They recovered one body on the beach, while the other one was brought up the cliff.
“Another man came up soaking wet and in a foil blanket. He knew them and had been trying to help. I’m just in shock, it was awful to watch.”