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Swimrun: What It Is, How It Works, and How to Get Started

Last Updated: March 19, 2026

What is Swimrun?

Swimrun is a multi-stage endurance sport where teams of two alternate between running and swimming multiple times without changing gear or stopping. Athletes run in their wetsuits and swim in their trail running shoes, moving continuously across varied terrain often with pull buoys and hand paddles. The sport originated in Sweden in 2006 from a drunken bet to race across the Stockholm archipelago.

Swimrunners typically race in swimrun-specific wetsuits that allow for easier running, well-draining trail running shoes, pull buoys for buoyancy, and hand paddles for swimming efficiency. Teams compete in three categories: mixed, women's, or men's. Solo divisions are also available at most races. Teams must stay within 10 meters of each other throughout the entire race.

How is Swimrun Different from Triathlon and Aquathlon?

Swimrun is often confused with triathlon or aquathlon, but the sports have fundamental differences in format, transitions, and gear.

Key Differences:

Swimrun features multiple swim-run transitions (typically 10-50 per race) with no gear changes. Athletes wear the same wetsuit and shoes from start to finish. Races are typically done in teams of two who must stay within 10 meters of each other. The continuous nature means athletes swim in trail running shoes and run in wetsuits for the entire event.

Triathlon combines three disciplines (swim, bike, run) with designated transition areas where athletes change gear completely. Triathlons are individual events with athletes competing solo. The bike leg distinguishes triathlon from swimrun fundamentally.

Aquathlon features one swim followed by one run with a single transition where athletes change from swimwear to running gear. Like triathlon, aquathlon is an individual sport with one transition zone.

Why the differences matter: The continuous transitions in swimrun create unique demands. Running in a wetsuit for hours challenges thermal regulation. Swimming in shoes requires different technique. The team format adds navigation and pacing coordination. These factors combine to make swimrun a distinct discipline, not just a variation of existing multisport formats.

Comparison Table

Feature Swimrun Triathlon Aquathlon
Disciplines Swimming + Running only Swimming + Cycling + Running Swimming + Running only
Transitions 10-50 transitions (continuous) 2 transitions (T1, T2) 1 transition
Gear Changes None - same gear start to finish Full gear changes at each transition Full gear change at transition
Running Gear Wetsuit worn for entire run Running kit (no wetsuit) Running kit (no wetsuit)
Swimming Gear Trail running shoes worn while swimming Swim-specific gear only Swim-specific gear only
Team Format Typically teams of 2 (10m proximity rule), solo options available Individual only Individual only
Terrain Technical trails, rocks, forests, open water Paved roads, pool or calm open water Paved roads, pool or calm open water
Typical Distance 15-75km total (varies widely) Sprint: 25.75km, Olympic: 51.5km, Ironman: 226km Sprint: 5-10km, Standard: 15-20km
Origin Sweden, 2002 France, 1920s-1970s Modern multisport variant
Key Challenge Thermal regulation, continuous transitions, team coordination Bike leg endurance, pacing across three disciplines Single transition efficiency
Swimrun in Maine

How do you “do” a swimrun?

Part of the beauty of swimrun is that there is no specific standard course or distance for an event. You run until you hit water and swim to the next run leg of the course, continuing this pattern throughout. Swimrun races are typically done as a team of two, but many races now offer solo categories. Athletes complete 10-50 transitions in a typical race, moving through nature in the most efficient way possible.

The objective is to move through nature as efficiently and cleanly as possible. Unlike triathlon, there are no designated transition zones. Athletes jump directly from running into water and from water back onto trails without stopping to change gear.

What gear do you need for swimrun?

Swimrun Orcas Island

When you're ready to try swimrun, you will need some gear to get started. The gear consists of a few main components. These are just high-level info about swimrun gear. If you want to take a deep dive, be sure to check out our Complete Guide to Swimrun Gear.

Essential Gear:

  • Swimrun specific wetsuit (designed for both running and swimming)

  • Trail running shoes with good drainage

  • Swim goggles (standard open water)

  • Race bib and cap provided by race organizer

  • Whistle (safety requirement)

  • Pull buoy (provides flotation while wearing shoes)

  • Hand paddles (improves swim efficiency)

  • Tether/bungee cord (3m/10ft, connects teammates)

  • Compression bandage (often mandatory)

  • Soft flask or cup (most races are cupless)

Gear Details

Swimrun Wetsuit: Check out our Swimrun wetsuit suit-out where we discuss all things you need to consider for a swimrun wetsuit.

Swimrun Shoes: If you are looking for more details about what makes a good swimrun shoe, check out our Swimrun shoedown.

Swimrun Pull Buoy: Having a swimrun pull buoy provides lots of flotation when swimming. This is really helpful especially since you are wearing your shoes during the event! Check out our YouTube video Swimrun Pull Buoy: Tips, Mounting & Mistakes for more pull buoy info.

Swim Paddles: We have a great Gear Talk episode where we talk about all things paddles for swimrun.

Swim Goggles: Just use your favorite open water goggles here. No need to overthink it.

Shin/Lower body floats (Optional): Most swimrunners use a swimrun pull buoy due to the incredible buoyancy advantage, but some people still like the shin floats.

Tether (Optional but recommended): One of the more interesting aspects of swimrun is the tether. Measuring 3m or 10ft, the tether was originally used for safety purposes to keep both teammates close to one another. Now the tether is used as an advantage where stronger teammates will pull each other during their respective strengths. Check out our episode on the swimrun tether.

Swimrun Undergarments & Socks: One of our more common questions! We also did great coverage of swimrun undergarments with our friends Annie and Brooke from the Swimrun Labs.

Mandatory Swimrun Race Gear: The mandatory race gear varies from race to race but usually consists of a whistle (one for each racer or one per team), a compression bandage (one per team), a soft flask or cup for drinking since most races are cupless, and race bib and cap.

What are the major swimrun races?

The sport has grown rapidly since its 2002 origin, with nearly 200 swimrun races on the 2026 global calendar spanning six continents. Major race organizations include ÖTILLÖ, ÖTILLÖ USA, Swimrunman, My SwimRun Championships, We Swimrun, Swimrun Portugal Series, As Keen As Mustard, Gritty Rascals Events, and Swimrun Australia.

For the most comprehensive resource, check out Dave's List, our complete global swimrun race directory with an interactive map and searchable database. The map lets you filter by country, month, and distance, making it easy to find races that match your schedule and experience level.

In the United States, races happen across multiple states including California, Washington, Texas, and Maine. ÖTILLÖ USA operates the ÖTILLÖ Swimrun World Series across North America, while the original ÖTILLÖ organization manages the World Championship in Sweden and European series races. For international destination racing and adventure guides, check out our International Swimrun Adventure Guide.

The ÖTILLÖ Swimrun World Championship is the pinnacle event in the sport. Held every September in the Stockholm Archipelago where swimrun was born, it's considered one of the most prestigious endurance races in the world. Dave's List includes all ÖTILLÖ World Series races, Merit Races, and tons of independent swimrun events worldwide.

How did swimrun start?

The history of swimrun begins with a drunken bet and a bar napkin course map of the Stockholm Archipelago in Utö Värdshus in 2002. The hotel owner challenged his friend and a few coworkers to a race where the bet was, "last team of two to Sandhamn pays for hotel, dinner, and drinks" according to Ötillö. As the story goes, it took them over 24 hours to complete and everyone was too tired to cash in on the free dinner and drinks.

Those four friends, sometimes called the Original 4, didn't know it at the time, but they started the sport we know and love, swimrun. The first swimrun race covered 75km across 26 islands in the Stockholm archipelago. The first commercial swimrun race was in 2006 with ÖTILLÖ (which means island to island in Swedish), and that same course is now the Swimrun World Championship.

According to the World Swimrun Federation, founded in 2015, the sport has grown from a single event in Sweden to over 400 races worldwide across Europe, North America, Asia-Pacific, and beyond..

 

Swimrun Photo Credit to Mark L Simmons Photography & AP Photoworks

training for swimrun

 
 

Swimrun Training

We share our thoughts on Swimrun training…thoughts formed from our many conversations with coaches, athletes, and our own training and racing experience. If you are just getting into the sport and need a place to start this will be for you! We break up our discussion on Swimrun training into three distinct training categories: physical fitness, fueling and hydration, and mental preparation.

Podcast: Here is the podcast episode and more in depth discussion we had.

Why are we doing this? 

We’ve noticed in our own training what has helped us show up to the start lines confident for the challenges (known and unknown) and we’ve developed a pattern or rhythm to our training, with the help of our coach, to get prepared. We obviously don’t know or claim to know all there is to know about endurance training but we’d had a lot of guests on the show that do. Make sure to check the show to get hyperlinks to our interviews to the coaches and experts that we’ll be alluding to during this episode. 

Anyway, we hope that you find our musings on training helpful.

Physical Fitness

Swim Training 

We’ve found that building a giant base of swim fitness leads to better race experiences and that the base helps increase your run fitness in the process. We think that de-coupling your swimming so that it is something that is always happening in the background at least 2-4 times per week will get you more than ready for any Swimrun outside of something like the One Water Race.

There are a ton of resources out there to improve your swimming but at the very least any organized Masters Swim group will help get you on the path.

Run Training

When it comes to training for the run portion of any Swimrun, we’ve found that getting specific to both the distance and terrain in your training is the best approach. If your upcoming race is super hilly, then you know what to do. Remember that a Swimrun that has 17 miles of running doesn’t mean that you need to be able to bang out 17 miles in one shot before race day. Since the run sections are broken up, you’re usually able to get by with shorter runs in the lead up. Obviously, the fitter you are on the run, the “easier” the race will feel and the more fun you’ll have out there.

Strength/Cross-Training

We all know that we need to do more strength/stretching/yoga/cross-training. Our approach is to start small and try to be ultra consistent. Keep nailing the fundamentals and you’ll soon build the habit and see the results on race day. 

Swimrun Training

Nothing simulates Swimrun better than a good’ole Swimrun practice. When you’re new to the sport these sessions are integral for you to learn the technique of Swimrun and work on all the little things that take up time during a race such as dealing with the tether, cabbing down, etc. 

We’ve found that as we have gotten more experienced in the sport these sessions are less about making sure that we have all the mechanics down and more about working on intensity and pace. We definitely do less Swimrun practices that we used to but we’ve developed the muscle memory for what works for us.

Previous LTBz episodes about Swimrun training: 

Mike Olzinski (EP 3 and EP 108)

Nicolas Remires (EP 14 and EP 126)

Nate Helming (EP 17)

Mario Fraioli (EP 30)

Gerry Rodrigues (EP 32)

Coach Jim Lube & Megan AMA

Ville Enburgh

John Stevens (EP 46 and EP 124)

Joe Friel (EP 115)

Fueling and Hydration

Gut Training

Just like anything else in Swimrun, you need to adapt to the unique challenges that these events can present. One of the biggest is fueling and hydration. Practicing what you will do on race day and having a nutrition plan in place is instrumental to maximizing your race performance on race day. Just as one would plan how they would tackle a difficult Swimrun course, you should also plan what you will do fueling wise. 

This is definitely a place where we feel that we have learned a ton as a team. We feel so lucky to have been able to work with Precision Fuel and Hydration and it’s no coincidence that our race performances have improved as a result. We highly recommend checking out all the free information that they offer and start working on your fueling and hydration training for your next Swimrun. 

Practicing Race Day fueling During Swimrun Training Sessions

This is a moving target that practice is key to nailing your strategy on race day. Just as you wouldn’t show up at a Swimrun without at least going through the paces a few times in your gear, practicing your strategy for race day is just as important.

Note that this is a moving target and as you get fitter, your fueling needs will evolve. 

Previous LTBz episodes about Fueling and Hydration:

Andy Blow (EP 25 and EP 118)

Abby Coleman (EP 120)

Mental Preparation 

Getting ready for the adventure of Swimrun isn’t just about being physically ready for the challenge, it is also about being mentally prepared for what lies ahead.

Get Aligned on Goals

Swimruns are great adventures that will test your body and mind. Whether you are racing solo or as part of team, getting aligned on what your goals are is key. Susie Moonan recommends that athletes be able to answer the question of “why?” Why are you doing this race is a great way to crystallize what you're hoping to get from the experience and this will help you if/when you hit a low point during a race. 

Be Realistic 

What does success look like? Or what should it look like? If you can go into a Swimrun with clear expectation on what success looks like you will be way more likely to find what you’re looking for in the sport. Swimrunning well is its own skill so don’t expect to be an expert at it your first time out. 

It has taken us years to get to the point where we feel like we know what we are doing…and we still take wrong turns sometimes.

Embrace the Ambiguity 

Similar to being realistic, embracing the nature of Swimrun is also key to having a successful race. Distances aren’t exact, aid stations may not be where you thought they were, and the weather can change rapidly. At risk of sounding totally tautological The more prepared you are for the randomness that you will experience during a race, the less of a mental challenge it will be when random things happen.

Previous LTBz episodes on the Mental Side of Things:

Susie Moonan (EP 54 and EP 122)

Brad Stulberg (EP 88 and EP 164)

Summary

So in summary, we think Swimrun training should look something like this:

  1. swim consistently at varying intensities;

  2. plan your run workouts to simulate the type of terrain and course that you will be racing;

  3. do enough Swimrun practices so that you are comfortable with your gear and the mechanics of Swimrun transitions;

  4. train your gut and start practicing your race day fueling and hydration well before race day; and

  5. think about why you’re racing Swimrun and line up your goals and expectations accordingly.

Swimrun Coaches:

If you are ready to take your swimrun training to the next level a coach that has the specific knowlege of swimrun is really helpful. We highly recommend that coaching resources such as Envol Swimrun, Tower 26, Simcoachen, Purple Patch, and TOT Endurance.

 
 

Swimrun FAQs

  • Simply put a Swimrun race is just called a Swimrun. Swimrun is an endurance sport that is usually done as a pair, but there is also a solo category offered. There are 3 divisions for each Swimrun race men’s, woman’s and mixed.

  • Swimrun-specific wetsuits typically have a front zipper (and sometimes a bonus zipper in the back), varied sleeve lengths (Long, short, sleeveless or removable), and are cut just above the knees. Swimrun wetsuits follow the “Goldilocks Rule;" some are made more for running, some more of swimming, and some that are right in the middle. These wetsuits will also come in varied thicknesses for different temperature conditions. Finally, most wetsuits do come in gender specific fit and sizing. For more information be sure to check out our Swimrun wetsuit guide.

  • A Swimrun can be as long as you want it to be! There are no specific or set distances or any swim or run legs during a Swimrun. Swimruns can be just a few kilometers with a handful of swims and runs or a long multi-day Swimrun adventure.

  • You are not required to swim in shoes during a Swimrun, but most swimrunners do swim in their shoes. The use of a pull buoy during the swim really helps to offset the drag caused by swimming in shoes.

  • To train for a Swimrun event we would recommend doing some run training and swim training. You can adjust your training to your own strengths and the type of Swimrun event you have coming up. We also find it very helpful to practice doing a Swimrun as it helps make the Swimrun transitions more smooth and quick.

  • Swimrun was invented in Sweden on the island of Utö at the Utö Värdshus hotel according to Ötillö.

  • Ötillö is both the brand name of a Swimrun race organization and the original Swimrun race which is now called Ötillö, the Swimrun World Championship.

  • Swimrun was invented in Sweden at Utö Värdshus in 2006 as a drunken bet between Anders Malm, Janne Lindberg and the Andersson brothers.

  • What you wear under your Swimrun wetsuit is up to you! Most people will usually wear some tight fighting non-cotton underwear bottoms or a swim bottom and top. Some folks ditch the undies altogether and only wear the wetsuit.

  • Yes! Socks play a key role in Swimrun. They help protect your shins and lower legs from rocks, debris, sticks, and other random things you encounter during a Swimrun. We recommend NOT using cotton socks or socks that have extra padding or cushioning in the footbed or toes (to prevent bogginess). Using a wicking sock like a thin running or cycling sock that is higher than ankle length is the way to go. Ankle socks could lead to getting more rocks or sand in your shoes.