The man had been jumping at Sharrow Point
A man suspected of "tombstoning" is in hospital with severe spinal injuries after jumping off a cliff into 3ft (90cm) of water.
The incident happened at Sharrow Point in Whitsand Bay, Cornwall, on Saturday.
The man in his 20s was rescued by beach lifeguards and airlifted to hospital strapped to a spinal board.
Dave Scullion, from Brixham Coastguard, said tombstoning - diving from height into water - was madness as tidal flows alter the depth of water dramatically.
The man, from Plymouth, jumped from a height of about 25ft (8m).
Coastguards said when he was rescued he was slipping in and out of consciousness and had no feeling in his legs.
The Tamar Coastguard Rescue team cleared the area while he was strapped to a spinal board and winched on a helicopter.
Mr Scullion added: "This is one way to ruin not only a pleasant afternoon for yourself, but very possibly the rest of your life.
"Tombstoning is madness whichever way you look at it. An individual has no real idea what's under the water they are jumping in and the tidal flows alter the depth of water dramatically."