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 |
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?
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