Jun Dai and Claudia Ashby were the next two women across the line.
A record 820 participants took a dip in the crystal blue waters, much to the delight of event director Scott Rice.
""We had the nicest weather conditions we've had in the series so far today, great for both swimmers and spectators. The swimmers were slightly challenged in the water with strong currents pushing them off course, so our times were a bit slower than previous years," he said.
"It was an amazing win for Brent. At 49 years old he is a very talented athlete and still very fit. It was a tactical win and he used his experience and maturity to push forward in the final seconds.
"It was a solid swim for Stefannie. She held her place amongst the male swimmers with a really smart and gutsy swim. She will be looking for a third win at the King of the Bays and is a real contender for the Series win."
Other distances in the Bay of Islands Classic event included the 300m 'Give it a Go' and the 200m Banana Boat OceanKids event.
There is one remaining event left in the 11th season of the New Zealand Ocean Swim Series, the King of the Bays on April 8 in Auckland.
The New Zealand Ocean Swim Series caters for swimmers of all skill sets and ages, offering an opportunity for recreational enthusiasts to take the plunge with some elite athletes.