The Arholma Lighthouse – Furusund Ferry FKT challenge

Arholma – Landsort: A Fastest Known Time swimrun adventure

To us, the Fastest Known Time (#FKT) concept is when you inspire others to beat a specific time someone has set on a point A-to-B distance. It’s not about mimicking a specific route at a certain date, but rather to challenge yourself to beat the fastest known time, by either going faster, smarter or both and when it suits you best.

– I love this kind of adventure where you get to decide on your own pace and route in the beautiful nature. There is an excitement to ending up in places where you normally won’t go, all while trying to swimrun you way towards the goal at point B, says Johanna Wallensten from Team Ultraswimrun.

There are no specific rules, but rather a principal outline for the challenge that follows a gentlemen’s agreement. To beat the current #FKT leaders, you should follow the same outline as they did, however with the option of choosing your own date and route. It’s common sense really, if the current team on top of the leader board didn’t have logistical support along their route, so shouldn’t you.

Team Ultraswimruns Arholma – Landsort FKT Challenge

This ultraswimrun challenge comprise of swimrunning through the whole of Stockholm arhicpelago, carrying all athletic equipment with you from the start (Point A), to the end (Point B). The challenge stretches over some 70 islands and 200-250 km of swimrunning. In the first attempt ever at this challenge, we Team Ultraswimrun, managed to swimrun a total of 160 km, stretching over 4 separate #FKT:s challenges. Thus, to date, we have set the first ever 5 FKT:s in the Stockholm archipelago for you to beat :).

  • FKT challenge: Arholma Lighthouse – Furusund Ferry 
  • FKT challenge: Furusund Ferry – Husarö Country Store
  • FKT challenge: Husarö Country Store – Runmarö North
  • FKT challenge: Runmarö North – Mörtö Bunsön North
  • FKT challenge: Arholma – Landsort

We will go through these FKT challenges in separate blogs, starting today with Arholma Lighthouse – Furusund Ferry (see below). In the coming weeks we will also upload all of our FKTs, including race bio:s and other stats, on and we hope to inspire you all to join us by sending us your #FKT challenges. This will enable and inspire the swimrun community to try to beat you at your own game ;). To log your FKT just check our webpage in the coming weeks.

/Team Ultraswimrun – See you out there!

FKT challenge: Arholma Lighthouse – Furusund Ferry

Run (approx, m) Swim (approx, m) GPS distance (tot, m) Fastest   known Time No. Runs No. Swims Tot no. legs
38 000 6 400 44 470 9:29:40 13 12 25

This FKT challenge starts at Arholma lighthouse, a.k.a Båk, which is also the start of the Arholma – Landsort FKT (ultraswimrun) challenge. A 3 minute walk from Båk lies the small harbour of Arholma, which hosts a small grocery store and access to fresh water and toilets. This harbour is suitable for unloading your expedition if you come with your own boat. You can also take the Waxholm ferry there if you plan to do the challenge completely unsupported. From Båk Lighthouse down to the end of Arholma you run on gravel road, but the last stretch takes you through trackless terrain, and here you will need the help of a map.


Leaving Arholma you pass some smaller islands and the larger island of Idö, after which you face a long swim over to Lidö. In the south of Lidö, you will pass Lidö Hostel, the start of the Amfibiemannen Swimrun race, which is a good place to have lunch if you’re not in a hurry to beat an existing #FKT 🙂

The swims around Lidö can be a bit dangerous since many boats pass here. If you don’t have a support boat or kayak of any kind, please make sure to swim together and use a safety buoy for visibility.

If you choose to go over Rådmansö you will face a long run on tarmac. We ran all the way down to Håtöviken where we started to cross a number of smaller islands, working our way towards Svartnö. During these crossings we ran on gravel roads and big and small trail. We had to run through people’s gardens since this stretch is densely populated. We never faced any problems, but then again we always made sure to run up to the property owner asking for permission to cross. Most of the time people just laughed, asking us why
the hell we were running in wet-suits and where we were going 🙂 During these swims, in the latter part of the challenge, we weren’t as affected by wind and currents as in the beginning, making us go faster than expected. 
Many times it was hard to enter and exit the water in the latter part, since we had to negotiate thick reed. On the upside, this stretch it was much easier to navigate given the shorter and calmer swims. Reaching Svartnö, we ran straight into a thick wall of fir trees and very rugged, pathless terrain. It took us quite some time to cross and reach the last easy 6 km run on tarmac, to reach the goal at Furusund Ferry. 

In the end our chosen route took us a total of 9 hours 29 minutes and 40 seconds to swimrun. It stretched 44 470 meters long and contained 13 runs and 12 swims in total.

Do you think you can beat us?

General remarks

This FKT challenge varies greatly with regards to running terrain and swimming conditions. Some islands were really hard to navigate because of the thick forests where we had to run solely on compass direction. Despite us thinking it would be easy to find our way on the densely populated islands, to our surprise, there existed many unmarked paths/tracks/roads, leaving that we from time to time got lost. This challenge can be approached in different ways depending on if you are a strong swimmer, going for the longer swims (to the east) and shorter runs. However then you’re more exposed to weather conditions which can be a tricky if you are going for the #FKT leaderboard. Be smart and use the weather and wind to you advantage.

We thought it would be easy to refill our small water bottles, but we rarely had this option since many people were’nt home. The same went for energy supplies. We thought we would come across smaller stores, which we didn’t leaving us dependent on the supplies we carried with us. 

Next to the goal at Furusund Ferry, in Ålandsviken, it’s possible for visitors to anchor their boat for the night (for a smaller fee). This fee includes access to hot showers, a sauna and toilets and if you ask nicely at the tourist office (the yellow house), they will let you to put up your tents just next to these facilities. There is a perfect lawn for the tents.

A 100 meters away, you have the Furusund Hostel. There you can enjoy well coocked food, but prices are in the upper range. If you’re looking for something more simple, there is a burger joint with reasonable prices just next to the ferry. You will also find a gas station here if you need to top up your boat. Furusund Ferry is accessible by car, leaving that it’s a short drive over to the mainland.

Good luck & if you beat us, send us the proof and we’ll put you on top of the leader board 😉

Stay tuned for our next challenge coming up 🙂

/Team Ultraswimrun

See you out there!

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