To do that, he first has to qualify the boat for New Zealand at the ISAF World Championships, which started in Perth on Saturday.
For Slater, that means finishing as one of the top 17 nations of 38 boats in the hugely demanding Finn class - racing in the Finn starts today.
If he can, he's virtually guaranteed an Olympic spot because he is the only elite New Zealand sailor in the Finn, which gives him a lot more certainty than those in other classes.
The Laser, for example, is a five-horse race with 2008 Olympian Andrew Murdoch, Sam Meech, Mike Bullot, Josh Junior and Andrew Maloney all vying for a ticket and Tom Ashley and J.P. Tobin are battling it out for the RS:X spot.
For Slater, this is his final Olympic campaign. He was eighth in the 49er class in Sydney in 2000 and a disappointing 12th in Beijing where, he said, virtually anything that could go wrong did.
"I can't see myself going beyond London," Slater says, "so this will be my last shot. Rio [in 2016] is going to be quite different because it's going to be a really light-air venue and it won't have the physical aspect London does."
London, of course, means Weymouth for the sailors, and Slater was seventh at the pre-Olympic regatta there this year. His entire focus is on the Games, meaning his training is geared to peaking then and not in Perth this week.
"In Perth, the Fremantle Doctor is an onshore breeze," he says. "It's quite steady so it's more of a drag race. In Weymouth, it's a shifty offshore breeze so it's a very tactical race and that suits my style. It's like sailing off Murrays Bay where all my training is done.
"I want to do as well as I can in Perth but the priority is to qualify the boat for London."
The world's best Finn sailors will be in Perth. Along with Ainslie, world champion Ed Wright is expected to be near the front of the fleet. The championships feature all 10 Olympic classes and sailors from more than 80 nations. They run until December 18.