We tried it: SwimRun

SwimRunners trek from sea to land. Aaron Palaian of PhotosByAaron.com

The bungee tether between my teammate and me caught on a nest of kelp as we swam, snapping us backward through the cold ocean water. Along the way we jumped off the edge of a pier. Then we got mildly lost, and later found ourselves wading waist deep in a creek while wearing wetsuits as mud pooled in our running shoes.

It was intense from the beginning, as hundreds of us huddled on the ferry on our way to the starting line in mid-August, asking each other: Do you know what you're doing? Do you have any tips?

We were on our way to the SwimRun USA Casco Bay race in Portland, Maine.

What is SwimRun?

SwimRun is a swimming-running race that allows participants to adventure across land and sea. Generally, the races traverse a series of islands -- running over one and swimming to the next. In Sweden, the birthplace of SwimRun, the most famous race series (which includes the world championship of sorts) is called ÖtillÖ, which means "island-to-island."

Because you travel from one island and finish on another, you must carry all your gear with you the whole time. That means running in your wetsuit and swimming in your sneakers. Since that can be kind of challenging, you're also allowed to use any swim assistance you want -- paddles, pull buoys, fins, etc. But all of those things have to be carried with you for the duration of the race, along with mandatory safety equipment like whistles, bandages and waterproof maps. Personal flotation aids larger than 40-by-24 inches are not permitted.

Plus, the whole thing is done in pairs, requiring you to stay within a set distance of your teammate. We couldn't be more than 10 yards apart throughout the event. Hence, the bungee rope.

And it all started as a bar bet in Sweden in 2002, morphing into a race by 2006. By 2014, SwimRun had become wildly popular in Europe and in 2016 it made its way to the United States. Today there are about a dozen events around North America -- some of which are more beginner-friendly and low-key, taking place in city parks and lakes. But the real spirit of the race is captured in the American original -- Casco Bay, along a wild string of Maine islands.

The details

This race is not easy. I can't tell you exactly how far it is, because the maps are approximate and the distance you cover depends on whether you get lost and which way you choose to swim. My partner and I covered more than 4.5 miles of swimming and 15 miles of running. Much of the race required us to scramble over rocks and trek through seaweed. On one rocky island, it took us more than 15 minutes to cover a half-mile.

Our motto was "basically ready" -- as in, we bought some bungee cord at a hardware store and practiced running together for the first time the day before the race. We said "basically ready" to each other throughout the whole five-and-a-half hours we were running (and laughing).

Because that's the real point of the event: it's supposed to be fun and crazy and hard. It's supposed to get back to the heart of the wacky races you do to see if you can handle them.

Having a partner is what makes this such an enjoyable experience. Having someone to celebrate and commiserate with makes the race exceptionally welcoming while still be incredibly challenging. Nearly 50 percent of the participants are women. And the co-ed/mixed division, in which the teams are made up of one woman and one man, is one of the biggest in the race and one of the most competitive. In many SwimRun races, the top co-ed teams win the whole thing outright.

Is it worth it?

This experience certainly isn't cheap. For example, it cost $750 per team for the Casco Bay long race. But you can cut corners and make do with existing equipment. Being such a new activity, everyone is still "MacGyvering" their way through the necessities. I created an elastic tie on my pull buoy held on by beer bottle caps and wrapped around my leg as I ran.

It'll be a little terrifying, but it's also the most fun you'll ever have at a race.

Kelly O'Mara is a professional triathlete outside San Francisco and produces a weekly triathlon-ish newsletter and podcast. Her work has appeared on NPR, Outside, Competitor and Triathlete Magazine.