Olympic rowing champion Joseph Sullivan is set to take the plunge.
And although he was the best in the world on the water, the retired gold medallist is undergoing a steep learning curve in competing under the surface.
Sullivan will be among 1,600 competitors taking part in the King of the Bays event at Takapuna Beach on April 18, signing on for the 300m "Give it a Go" race. Other distances on offer in the swim series include the 1km "Step it Up" and 2.8km "I'm Going Long".
Despite the countless hours Sullivan spent on lakes during his champion rowing career - which included winning gold with Nathan Cohen in the men's double sculls at the 2012 London Olympics - he said his swimming ability wasn't that flash.
"It's not fantastic, in fact it's quite poor," Sullivan told the
Herald on Sunday
.
"I thought I'd take up the challenge to push myself and get a bit better.
"[But] I'm only doing the short race and should be able to struggle my way through it."
Sullivan, who turns 28 next Saturday, retired from rowing last June. On top of the Olympic gold, he won back-to-back world championships with Cohen in 2010 and 2011.
The pair's Olympic triumph won them the fan-voted Halberg Award for New Zealand's favourite sporting moment of 2012. He has since became a firefighter.
"It can be a terrifying job, but I enjoy it," he said.
"I've been to a few house fires already and, thankfully, everybody was out in time.
"But I'm yet to have my first critical incident.
"I didn't have time to do anything else when I was rowing. All my time and energy was dedicated to that.
"These days, I'm getting into my new job and am enjoying having a bit more of a social life, too."