It happened in 2002. Very similar to drunken bet in Hawaii. The first one gave birth to Ironman, this one from Sweden gave birth to one of the fastest growing multi sports ever. Is it possible to cross multiple islands in Stockholm archipelago using just my own powers? Yes it is! And the process of doing so is so tough and exciting at the same time. Otillo World Championships is to swimrunners, what Ironman Kona is to triathletes.

It’s not triathlon without bike, it’s not aquathlon. Multiple changes between both disciplines and no transition areas. This style of course brings participants quite often to unique places, they would never be able to visit otherwise. The race is usually either sea swim crossing the islands along the way, following the seashore partly by swimming and partly running or running along, while crossing multiple lakes, dams and/or rivers.

As for the equipment, everything what you start with, you have to bring to the finish (including your partner:-)). You can find swimruns as short as 6k and also even longer then 100k. Typically the swim parts are between 100 and 2000m (mostly around 300m) and run parts between 200m and 20k (mostly around 2k). Frequent interchange between running (legs hurting) and swimming (legs resting) allows you to cover longer distance compared to continuous running.


Compared to triathlon, on of the main differences is the necessity to find a proper partner. Ideally someone, who is about the same swimming and running speed across given distance. You can make-up for a small difference with tether (quite a staple for mix couples), but it has its limitations. If you enter the race to just enjoy the process and scenery, even bigger difference in speeds is quite OK. Whenever you get competitive, it soon makes someone unhappy. Either the slower one for slowing down the partner or the faster one for not being able to show his full potential. If you are not lucky enough to know/find someone adequate in your neighbourhood, try to register at this site for any specific race in the world and find other people willing to race there sorted by the proximity to your swim and run times. You can start the chat immediately. You can find a lifetime swimrun partner, someone to replace your injured buddy just for one race or a local partner for a race at different continent (where you travel for business or leisure). Regardless of your relative speeds, you should be ready to share the experience and support each other through everything, which can happen. Being there for your buddy is one of the major staples of swimrun.

The course marking is usually quite minimalistic, but with detailed race maps and other people on the course with you, loosing the way is actually quite rare. Hid stations are mostly available, but expect to have your own collapsible cap for drinks (or use your swim cup) and don’t litter anywhere past the aid station. All wrappers has to be brought to the finish line on you.


You should first be ready to do running and swimming sessions similar to the typical triathlon training program. Working on endurance, speed, power,… Make sure to be able to swim properly with swim paddles (smaller at the beginning and bigger as you progress) as those are allowed in the races to counteract dragging shoes in the water. Also try to plan as much of your running on challenging trails as possible, as you won’t really meet any kind of asphalt or pavement at most races. Once your ability to swim and run the distance is there, the time to get ready for specific sessions comes. You can begin with just continuous interchange between swimming and running. As there are no transition areas in swimruns, you clearly run off the water and run into the water as the race dictates. So for the first phase, it is ideal to find a pool or open water in proximity to sandy beach or grassy area. There all you need is to continuously swim (100-500m) and run (500-2000m) without stopping in your swimsuit. Once you sort out your equipment (see section below) for the race, you should be practicing partially or even completely in it. That will help you to master necessary “transition” moves (putting on/off your googles, swim cup and paddles, placing/displacing your pull-buoy, zipping/unzipping your wetsuit,…). And with your running shoes on, your area for practicing now increases substantially. You can run pretty much anywhere and you can also get into and out of the water in most places. Just make sure it’s legal to be there and don’t swim around land fences into dangerous areas… Mastering various kinds of entry and exit points (mud, rocks, sand, vegetation,….) is really part of the game, as some swimruns are quite demanding in that aspect. And the same goes with the ability to make “transition” moves quickly - you will usually do that 10+ times in a race and being a bit slower there might cost you a contact with your competition and a lot of time as a result.



For you first short swimrun you can be fine with your regular triathlon wetsuit or even just a trisuit (according to air and water temperature). For warmer temperatures, quite often Blueseventy Core shorts combined with trisuit and neoprene calf gueards might be a reasonable solution. But for longer races and especially for all races with cold water, you should be racing in swimrun specific wetsuit. It usually has short legs (for easier running), long arms, which can be cut as needed, set of inner and outer pockets for equipment, front zipper for easy ventilation while running,… My preference is Blueseventy Alliance wetsuit cut to short sleeves. Whenever the water is too cold, I can put back the rest of the sleeves and it holds perfectly as an original long sleeve.


For those, wide range of vision is a must. You won’t have a buoy every hundred meters. You should be able to always spot a buoy or swim exit, but it may be quite far. Also seeing your partner underwater at all times is very important. Opt for softer silicone sockets and polarised lenses, so that you can survive occasional face kick from your buddy and see properly under all light conditions. I always use Hydravision Blueseventy goggles with polarised lenses.


Aim for breathing, quick drying and non chafing material. Some brands are also selling specific models with additional pockets on them for storage. Net like material from swedish brand Brynje is the best, I ever had for this.


To make up for dragging shoes, you can elevate your legs with pull-buoy. You should attach it either to one of your tights with two straps or to a waist belt with one strap. The easier it is to move it away and back, the faster will be your transitions. Make sure it is not disturbingly bouncing, when you run (even down the steep descents). I prefer the bigger version sold by Racepaddles.


Same as the pull-boy, these are allowed to improve your swim speed. The shape and size is quite critical. It should be sit comfortably, when you swim and turn around or disengage easily, when running. Adjust their size to a distance covered. When there is total of 2k swim, you can be fine with L size, while for longer race with 8k of swimming, M size may be better for your arms and shoulders to survive… I am using carbon blade Racepaddles, which are very light. A bit sharp on the edges too and after scratching my wrists at some races with difficult water exits, I added a textile tape to the wrist edge for protection.


Another way how to counteract the drag of the shoes, while swimming. Those are also a great protection for difficult water exits and dense low vegetation.


You can either use low socks or compression full length socks. Just make sure, those are lightweight and quick drying. Always go through many swim-run transitions with them in training to make sure, there is no problem and blisters. At best, try to imitate race conditions as close as possible (sea water, sand, rocks, mud,…). My preference is a pair FXC compression socks. Me and my partner did Otillo World Championships in those with zero blisters.


Another option how to increase your buoyancy is using neoprene calf guards. Unlike pull buoy, there is no need to tackle with them in transitions. They also offer a great protection for your legs and compression socks when getting out of the water by crawling/climbing and when running in a dense vegetation. I use Blueseventy calf guards with up to 7mm width on the front panel.


Probably the second most important item right after the swimrun specific wetsuit. You will need a pair of trail running shoes, which are light and not bulky. It is very important, that they can drain water quickly and the sole has perfect grip on wet surfaces. My preference is Salming OT Comp, which took me safely and quickly through all my swimruns so far.


Yes! It is allowed to use those in swimrun competitions and it can make your swim a lot faster. On the other hand, your transitions will get significantly slower (even if you find a flipper fitting over your whole shoe), you will have to wear them somehow while running and your legs won’t be resting through the swim compared to your competitors using traditional pull-buoy - neoprene calf guards combo.


It’s not completely necessary, but having it, you don’t need to have additional compass and after preloading the watch with gpx course map, the watch can guard you when you are getting out of the sight of other competitors or race markings. My best friend is Garmin 945, which also provides preloaded swimrun profile for continuous swim - run - swim segments and at the end provides you with cumulative data for each discipline separately.


Usually provided by the race organiser to identify all athletes easily, this is typically mandatory piece of equipment. On a hot days, it can usually be taken off while running, but needs to be back on the head for all swim segments. For cold weather/water temperatures it is a good idea to have a second cap underneath - either silicon for mild temps or neoprene one for really cold water. I am using Blueseventy thermal cap, which tightly covers my ears as well.


Necessity for some people while swimming (especially in a very cold water). Make sure to have those connected with longer rope together, so that you won’t lose them. Or try the thermal swim cap covering the ear, which can solve the problem even without the plugs.


This can and will vary based on a specific rules for each race. ÖtillÖ series races usually require a first aid bandage in waterproof packaging, a compass or watch compass and a whistle. And a part of your registration packet will be a swim hat, race bib (usually a singlet over your wetsuit), timing chip and map.


Especially when you and your partner are of a different swim or/and run speeds, toe line might be a right solution to stay together and be a bit faster. You will also need a pair of belts for attachment of the toe line (usually with small carbines). Even if you are of similar speed (you found each other via, you can use the toe line in the water for better orientation and connection and on the run, when one of you is going through the rough patch. Make sure to cut it for the right length, so that in the water the toed person is putting his palms to the water 10-20cm behind the front swimmer. That increases the draft effect and also prevents others from swimming in between the two of you. That can be a big trouble in a first few dense swim segments… When you decide to separate for the run section, just circle the line around the waste and secure with the carbine. You can make the toe line from cheap expander line (not too rigid or too loose).