Everything You Need to Know About Swimrun

Athletes running out of the water

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If you’re passionate about endurance sports, consider adding a Swimrun event to your race calendar. This multisport competition features the unique challenge of consistently switching between swimming and running, in either a standard race course style or in a loop course.

Though certain events are focused on experienced long-course athletes, there are also several beginner-friendly short-course Swimrun events!

History of Swimrun

Swimrun is truly in its infancy compared to other endurance events. The first organized marathon took place as early as 1896 and the first modern triathlon in 1974 – but the first organized Swimrun event did not take place until 2006.

The origins of Swimrun started a few years earlier, in 2002, with a group of four friends in Sweden. The friends challenged each other to conquer a portion of the Stockholm archipelago by sea and foot, from Utö to Sandhamn. They broke into two pairs, and it took each more than 26 hours to complete the challenge.

In 2006, Michael Lemmel, an adventure racer with a sports marketing company, was asked to make a commercial event out of this style of racing. He met with the original friends from Sweden and watched them via safety boat as they did a trial run of a course outline. At the end of the trial run, he decided to move forward with planning the event.

The inaugural Swimrun was named ÖTILLÖ, translated as “island to island” in Swedish. Held in September 2006, it included nine pairs of athletes – but only two teams finished. The event garnered media attention as being one of the toughest endurance events in the world.

Later in 2012, additional Swimrun events began appearing in Sweden. In subsequent years, events began to pop up in other countries. Experts estimate there are now more than 400 Swimrun events around the world, and the sport continues to grow.

Types of Swimrun Events

The traditional ÖTILLÖ style Swimrun is done with a partner on a standard style racecourse. As the sport has expanded in popularity, though, race organizers now offer different style events to accommodate everyone’s needs. Here’s a quick overview of each type:

Traditional Course With a Partner

A traditional course event will either be a point-to-point event, or a course that starts and finishes in the same location (but does not loop the same segments).

Most Swimrun events feature this type of course and involve a partner. Partners must stay within 10 meters of each other throughout the race. To make this easier to manage, many partners choose to tether to each other during the swim.

Traditional Course Without a Partner

In this case, the course style is the same, but the race is done solo without a partner. This is starting to become an add-on to many events that historically only offered partner registrations. Since finding a partner can be a barrier to entry, offering solo athletes the ability to race helps increase registrations.

Loop Course Without a Partner

Unlike a traditional course, a loop course has one swim leg and one run leg. You’ll be challenged to complete the combination with a certain loop goal (i.e. a 3-loop race) or by completing as many loops as possible in a certain time frame (i.e. a 4 hour race). These events tend to be individual rather than partner events.

Training for Swimrun Events

Training for Swimrun is similar to most other endurance training, and generally broken into three phases:

1. Aerobic Base

You’ll first want to build an aerobic base in both the run and swim disciplines.

In this phase, incorporate several runs each week that focus on building distance at a comfortable pace, with one speedwork or hill session built-in weekly.

For swims, include several sessions each week as well. Work on both drills that improve form as well as comfortable long-course swims that enhance endurance capacity.

2. Race-Specific Training

From there, you’ll build to race-specific training. This might include more long course swims with gear (like paddles or being tethered to a partner), race simulation workouts, adding in more technical trail running and interval runs, or other tasks that help you prepare for the specific event.

3. Taper & Race

Lastly, you’ll end training with a short taper, where you'll reduce training volume in the 1 to 3 weeks before the event. This will help you arrive feeling fresh on race day.

Additional Training Tips

A coach can help you put together an ideal training plan based on your fitness level, course choice, and race goals. In the meantime, consider these additional tips to help you prepare:

Train in Open Water

Tackling tons of laps in a pool is wonderful, but doing the same distance in a lake or ocean is a whole different experience. People often develop a fear of not seeing the bottom, get nervous about living things in the water, have trouble with sighting, or sometimes panic about not having anything to grab hold to. 

In addition, the unique nature of Swimrun where one is alternating between both disciplines increases the likelihood of muscle cramping in the water for poorly trained athletes.

At a minimum, these issues can make for poor performance – and in more severe cases, panic or cramping in the water can lead to significant safety concerns.

If you decide to sign up for a Swimrun event, be sure you are comfortable with open water swimming. Train as much as possible in the open water. Take safety precautions when practicing, like swimming in a group setting, using a safety bouy, letting others know your estimated time in the water, and/or hugging the shoreline (especially if you need to practice alone).

Practice Sighting

While in triathlon there are generally large buoys to sight, this is not the case for many Swimrun events. You may be sighting a small beach or small flag in the distance.

When you train in open water, practice sighting small objects in the distance and swim as straight as possible to them.

Understand the Course

Your training should be adapted based on the specific attributes of the course. For example:

  • Is the course swim heavy, or is it more run focused? Your training plan should consider both your personal strengths/weaknesses, as well as how the course is structured.
  • Are the runs on roads or trails? This will impact what terrain you need to practice on during training.
  • Are the swim segments in lakes and ponds, or are they in the ocean? If in the ocean, what are water conditions typically like? If the water is almost always choppy, you’ll want to have some experience in those types of conditions.
  • What’s the expected weather on race day? If it’s going to be very hot, you’ll want to make sure you are comfortable and acclimated to running in the heat.

Do Race Simulation Training

While many triathletes are familiar with the feeling of switching from one discipline to another, Swimrun becomes new territory as you have to consistently go back and forth. Be sure to build in some race simulation workouts, where you practice alternating between disciplines. This will help you better understand the realities of race day and also builds confidence on your abilities.

Choose the Right Partner

If you choose to do a Swimrun event with a partner, keep in mind that you’ll want to choose someone of similar athletic ability. Because you must stay together for the entire race, it can be frustrating to choose a partner that’s considerably faster or slower than you. 

Teaming up with someone that runs the same speed and swims somewhat similarly will ensure you have a positive race experience.

In addition, be sure their demeanor under stress is relatively positive. It’s a long day for both of you during a race and mental fatigue is just as essential to manage as physical fatigue. A partner that handles stress well and can stay positive helps you both through the tough times.

Suggested Gear

Unlike a triathlon where you have the ability to remove or add gear between disciplines, swimrun requires you to stay in the same gear throughout the event. That means you’ll swim in your sneakers, and run in whatever you wore during the swim.

Keep in mind gear requirements will vary based on the length of the event and water temperature. For example, if you’re a beginner doing a short course event in a comfortable temperature water, you may not need any special gear. You can swim in a tri suit (or running shorts and swimsuit top) with a pair of lightweight sneakers.

But for longer events or more elite events, you’ll probably need to stock up on a few pieces. As the sport continues to grow in popularity, more specialty gear is hitting the market. Here are a few items to consider:


This is the one piece of gear that everyone will need, regardless of race distance, course type, or fitness level. Make sure the goggles you are using fit well and don't fog up. If you’re doing a long course race, it may be helpful to have a backup pair on hand that fit both you and your partner (if you’re racing in a team).

Swimrun wetsuits

For many swimming events in rough and/or cold water, a wetsuit is helpful for both buoyancy and thermal regulation. In some events, they may be mandatory.

That said, a standard full-body wetsuit (like you may own for triathlons) is not always comfortable or feasible for running. Some athletes take an old triathlon wetsuit and cut the legs and sleeves for a makeshift Swimrun wetsuit.

At this point, there are several Swimrun specific wetsuits on the market which is probably your best bet if you are pursuing the sport seriously. These are generally “shorts style”, allowing the legs more flexibility for the running portion.

At this point, there are several Swimrun specific wetsuits on the market which is probably your best bet if you are pursuing the sport seriously. These are generally “shorts style”, allowing the legs more flexibility for the running portion.

These wetsuits come in either full sleeve or short sleeve, depending on your preference and anticipated water temperature. Some of the long sleeve suits have removable arms, and most have a front zip option to allow for heat management during the run.


Since you’ll both swim and run in your shoes, they should be a pair that drain water quickly and are rather lightweight. The last thing you want is to feel like you’re running with soggy bricks on your feet. Shoes with a mesh upper or those that are specifically designed for water-to-road conditions are ideal.

With all the water entries and exits, as well as possible off-road running, it’s also helpful to look for sneakers geared for trails with a grippy bottom. This can help prevent slipping on rocks as you exit the water as well as help you on the trail runs.


There are two types of buoys you might see in an event like this – a pull buoy and a tow buoy.

Pull Buoy

A pull buoy is a piece of foam that’s shaped like a figure eight. During the swim, it’s placed between the legs which helps the lower half of the body float. This allows the swimmer to focus more on their arm stroke, conserving leg energy for the run portions of the race.

For Swimrun, the pull buoy is attached to the leg via an elastic band. You can finagle this yourself with a pull buoy you already have lying around, or you can buy one that has the band.

When you exit a swim leg, you’ll shift the pull buoy to the outer part of the leg so you can run comfortably. Then when you enter a swim leg again, you’ll swing it back around between the legs.

Tow Float

A tow buoy also called a tow float or swim buoy, is a brightly colored inflatable oval that’s attached to you via a waistband. There’s usually one or two feet of extra line where it attaches to the waist, so it drags behind you when you swim.

There are several purposes to using one of these. In some races, they’re mandatory for athlete safety, as it helps rescue workers better spot athletes in the water. Many can also act as a dry bag, where you can store nutrition products as you transverse the water.


To make for a more efficient swim, many Swimrun athletes use paddles. These thin paddles are held in the hand to help you propel you with each stroke. They’re inexpensive and one of the best “extra” pieces of gear you can have in an event.

After you finish a swim leg, you can either flip the paddles around to the back of your hands while running or remove them and tuck them into your wetsuit.

Keep in mind that though large paddles seem like the best choice because they catch a larger surface area of water – they also will cause you to fatigue more quickly, specifically in the back and shoulders. Be sure to choose the right size paddle for your swim level, and also be sure to practice with them in advance of the race.

Neoprene Swim Cap

In almost any race, you’ll receive a swim cap from the organizers. However, if the water temperature is very cold, it might be worthwhile to also get a neoprene swim cap. This can be worn underneath the race swim cap and helps seal in warmth.


If you’re in a race that requires partners, you’ll probably want a tether to stay connected to your partner (at least during the swim portion; some teams untether during the run).

Since you have to stay within a certain distance of your partner, being tethered makes it far easier to do that on a swim. This is especially true at the start of the race when everyone is in the water together – it can be hard to spot your partner when all the athletes have similar gear and swim caps on!

In addition, being tethered together during the swim allows one swimmer to pull the other a bit, and let the second swimmer draft. You’ll definitely want to practice this with your partner several times in advance of race day.


Swimrun races are definitely endurance events, and even short course races will typically take at least a couple hours. While there are aid stations present on courses, it’s a good idea to carry a few spare gels or other fuel of your choice. In the event a segment takes you longer than anticipated or you simply feel like you need more calories, having spare fuel will prove valuable.

Mandatory gear

Some races will require certain mandatory gear to be carried on you at all times. This may include a compass, a whistle, and a pressure bandage. The contents and necessity of any mandatory equipment will vary from race to race, so be sure to read the athlete guide prior to the event.

A Word from Verywell

While Swimrun might seem intimidating, it’s also an amazing challenge that you can tackle with the right guidance. Choose a race that’s good for your skill level, decide between a solo event and a partner race, and put the time into training properly – then cross that finish line with pride!

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