The 31st annual Swim Across America Long Island Sound Swim open water event benefiting cancer research took place Saturday in Larchmont.

Participants swam 2K, 5K or 10K – all for a good cause.

The Long Island Sound Swim is one of the oldest and largest Swim Across America events in the country.

"We've been doing this for 31 years right here in Larchmont. We started with 15 swimmers, [raising] $15,000," said Jean Fufidio, Swim Across America Long Island Sound Swim director and chair.

The event has grown tremendously over the decades. Organizers said over 500 people participated in Saturday's event.

Many participants have personal ties to the cause, like Judy Anker, who was diagnosed with leukemia herself. She also swam in memory of a loved one.

"My daughter had melanoma. She passed away three years ago and I swim for her," Anker said.

As participation increases, so do the donations. Organizers hoped to break a major fundraising record this year.

"We will break our $25 million mark of raising funding,” Fufidio said.

All the proceeds will go to local beneficiaries, like Weill Cornell Medicine.

"It allows us to take risks and explore new areas so that we can continue to make progress in the area of cancer treatment," said Weill Cornell Medicine's Dr. Jedd Wolchok.

His colleague, Dr. Taha Merghoub, said their team is trying to test the efficacy of immune-based therapies.

"Until now, this immune therapy treats a certain amount of patients. Certain patients respond to it and some don't, so what we're trying to do is make sure that everybody responds to this therapy," Merghoub said.