After a successful first run last year, the Islander Aquathon returns, this time with two chances for people to give it a try.

As part of the new Pacific Aquathon Series, the Island event will be held on Aug. 3 and Aug. 31 at Luther Burbank Park.

Last year, BTO Multi Sport race director Porter Bratten said he hoped to expand into a series. The large numbers of participants made this summer’s series possible. The first race of the five-part series will take place at Seward Park, then Mercer Island, back to Seward and finally back to the Island, all on Wednesdays. The fifth race will be held in Des Moines on a Saturday morning.

“We had 225 people last year,” said Bratten of the Island Aquathon. “Hopefully a lot of the same people are coming this year.”

An aquathon, unlike a triathlon, has just running and swimming legs. Bratten said this makes it easier for people to compete, because they don’t need a fancy bike, just a swim suit and running shoes. The Island races begin in the lake at the Luther Burbank swim beach, and the running course winds through the park.

During the Mercer Island races, participants can choose to do a 500-meter swim and a 5k run, or a longer version, which is a 1k swim and 10k run. All of the other races feature just the shorter format.

“There are a lot of good reasons to come out,” said Bratten. “It’s a weekday evening, so this is logistically easy and it’s done and over quickly. The distances are short enough that anyone can do it, and the venues are beautiful.”

Bratten said he chose Seward Park as part of the series because of its location, and so many people are used to swimming there.

“It’s a good location, close to Seattle, and close enough to Bellevue,” he said. “People are already pretty familiar with swimming there, and it’s a good trail and nice views.”

Des Moines was added to the list because Bratten, a Mount Rainier High School graduate, knew the area well, and had long wanted to host a triathlon there. He said there were safety concerns with the biking portion of the race, so when he expanded the aquathon into a series, it made sense to try it down there.

“There are far fewer events down there,” said Bratten. “Because of that, it made sense to do it on a Saturday.”

A change from last year’s event is the raffle this summer. Bratten said he has partnered with Food Lifeline, a hunger relief organization, to help donate food. Every person who registers for the race, and then brings at least two nonperishable food items to the event, will be entered into the race’s raffle drawing. Bratten said there are a wide array of prizes, such as water bottles, T-shirts and more.

Outside the raffle, Bratten said the Mercer Island races are again sponsored by Dilettante chocolates, so there will be plenty around.

Each race individually is $35, but Bratten said signing up for multiple races will give participants a price break. T-shirts for the event will be sold separately for $25.

The Mercer Island races begin at 6:15 p.m. and the Seward Park events start at 7:30 p.m. The Squidman Aquathon at Des Moines Beach Park will have an 8:30 a.m. start on Aug. 13. Bratten said registration for each race closes at noon the day before, but same-day registration is available. He recommends getting to the race site an hour ahead of time.

“The whole point of the Wednesday night event is that it’s a little more informal and more relaxed,” said Bratten.

Bratten said if this summer’s series is successful, he hopes to expand again next summer, possibly to Juanita Beach Park and to Magnuson Park in Seattle. Either way the aquathon will be back on Mercer Island next summer as Bratten’s race was chosen to host the 2012 Aquathon National Championships at the end of July. It will attract swimmers and runners from across the country.

“I filled out an application, and I think they were impressed with the location,” he said.

To register for any of the Pacific Aquathon Series races, or just the ones on Mercer Island, visit www.btomultisports.com.