Rough conditions pounded the 1500 swimmers in the Harbour Crossing race in Auckland yesterday.
Australian Trent Grimsey, 24, led the 2.9km swim from Bayswater to the Viaduct Harbour in 35m 09s, ahead of two countrymen, double Olympian Ky Hurst and his brother Codie, who won in 2010.
Winds of up to 30 knots made the water extremely choppy.
"This was probably as tough as any race I've done in terms of the conditions," Grimsey said.
"It is a lot harder to swim in the chop than in flat water, but I think it affected my competitors a bit more than me.
"I don't mind it when it's like this."
The women's race was won by defending champion Cara Baker, 22, but only after a navigational error 200m from the finish by rival Charlotte Webby, 24, who swam to the left of a marker buoy when she should have swum to the right of it.
Both are Kiwis. Webby led Baker for most of the State Insurance-sponsored race. Baker finished in 39m 56s.
"It was really unfortunate for her," Baker said. "Maybe it was my good fortune to go on her right side. I was certainly surprised to see the tape out for me, not her, when I got out of the water."
Webby, who was 15 seconds behind, said she was gutted.
"It was my mistake. I was really hoping for a win against her. Cara's an awesome swimmer."