Jo Brooksbank found the underwater ride hard going
A mother-of-two dived into the sea and cycled under Brighton Pier to encourage more women to take up cycling.
Jo Brooksbank, 43, who lives and works in the city, used a conventional road bike for the underwater stunt.
The bike was first thrown into the sea with a marker buoy attached to it before Ms Brooksbank jumped into the water from a dive platform.
The experienced diver and keen cyclist said she cycled underwater for about half-an-hour on Thursday morning.
Mrs Brooksbank, who works as a transport officer for Brighton council, has degrees in marine biology and marine management and is a qualified cycling instructor.
She said: "It all stems from seeing a picture about 20 years ago in a magazine, of a diver sitting on a bike, just floating down through the water.
"It's obviously a strong image, because it stuck with me.
"I've got back into cycling over the past three years after having my children, and this has helped me to get fit and back into shape."
After the stunt, she said: "It was a lot more tiring than I was expecting it to be.
"There's quite a bit of current coming past under the pier.
"We managed to find a smooth-ish area in the end, and we kind-of got cycling - a bit more wheeling than cycling I think - but I think we can say we did it."