Australia have launched their 2025 SailGP campaign with authority, snatching the lead after the opening day of racing in Dubai.

Tom Slingsby's crew had finishes of 3-5-1 aboard their Flying Roo 50-foot foiling catamaran to take a 24-23 lead over New Zealand, skippered by Peter Burling, who is coming off his third straight America's Cup victory.

Diego Botin of Spain, who stunned Slingsby and Burling to take the $US2 million, winner-take-all Grand Final of Season 4 in July, was seventh in the 11-boat fleet, the largest in SailGP history.

The powerhouse Aussies and Kiwis weren't slowed by defections of key crew members to other teams.

Slingsby, who won the first three season championships in tech titan Larry Ellison's global league, credited new wing trimmer Chris Draper with helping to master the light wind, which traditionally has been the team's weak spot.

Draper signed after Kyle Langford, who had been with Australia since SailGP's debut in 2019, jumped to Jimmy Spithill's new Red Bull Italy team.

"We all know Chris' ability in the light air and he has brought a lot of experience to the team in that area," Slingsby said. "We are so happy to have him onboard and it showed today that he is a seamless fit for our team."

Slingsby timed his start perfectly in the third race and pulled away to win by more than two minutes over Emirates GBR and theirnew helmsman, Dylan Fletcher. Two-time Olympic gold medalist Martine Grael, the first woman to helm a SailGP boat, had a dramatic final sprint to overtake four boats and finish sixth.

"We could not be happier," Slingsby said. "We had a really good day and a good start to the season. We need to turn our efforts to having a good day tomorrow to make sure we get into that final."

The top three teams after Sunday's two fleet races will advance to the podium race.

Emirates GBR, Canada and the United States are tied for third with 18 points each, followed by Switzerland with 17, Spain 16 and Germany 15. Italy, helmed by two-time Olympic gold medalist Ruggero Tita, is last after going 10-11-9.

The Kiwis had to replace flight controller Andy Maloney, who jumped to the Brazilian team. Burling said new flight controller Leo Takahashi meshed well with wing trimmer Blair Tuke to help the Black Foils go 2-3-5.

"It feels like it's been a long time since we've been racing and it was a tough and shifty day," Burling said. "It was a pretty pleasing day for us with the changes on board that we managed to perform at that level so quickly. Blair and Leo are doing a super job getting the boat to go so fast in those conditions, so I'm pleased with those three races."

Taylor Canfield and the United States won the opening race while Erik Heil and Germany won the second race.