Experience nature in open water


Experience nature in open water

Rondje Pampus is an unique open water swimming event organized annually to draw attention to the vulnerable nature in the IJsselmeer region of The Netherlands. Swimming in open water around Fort Island Pampus is spectacular for both recreational and competitive swimmers. A sporting challenge while enjoying the vastness around you, of wind, waves and water. Because you truly experience nature in open water!

Participants in Rondje Pampus contribute part of their entry fee to a good nature cause. Last year, for example, participants helped restore the Frisian bird ringing stations in the Makkumer Súdwaard in the Dutch provence of Friesland. This year, part of the entry fee will be donated to research into otter habitat in the provence of North Holland.

Otter habitat research

Every year the participants in Rondje Pampus swim for a good nature cause. This year the participants swim for the otter and a very special one indeed! The otter has been spotted near Amsterdam in IJdoorn, a polder outside the dikes near Durgerdam, and possibly also in the Ilperveld nature reserve in the provence of North Holland. This is special news because these animals are not normally found so close to urban areas. The otter is a protected species and it is great to see it is showing up in our country again.

Landschap Noord-Holland will research the habitat of this otter, which seems to move between IJdoorn and the Ilperveld. Why does he do that, what makes both areas attractive to him and what does he need to settle permanently?

The otter is an important part of our ecosystem and it is great to see that these magnificent animals are back in The Netherlands. So this year, in cooperation with Coalitie Blauwe Hart Natuurlijk, the Rondje Pampus Foundation is therefore making a financial contribution to this unique research by Landschap Noord-Holland. Making sure we take good care of the otter so we can enjoy their presence for a long time to come.

Fort Island Pampus

Rondje Pampus takes place on and around the unique Fort Island Pampus. Pampus (officially Fort aan het Pampus) is a fortress island in the part of the IJmeer that belongs to the municipality of Gooise Meren. The artificial island was built in 1887 as part of the Defence Line of Amsterdam to defend the channel Pampus against attacks from the Zuiderzee.

Sunk into the island is the massive Fort on Pampus. Once built to defend the entrance to Amsterdam through the IJ, it is now an abandoned ruin. The fort stands on 4,000 piles 11 meters long, and the buildings are a combination of concrete and masonry bricks. The fort has an oval shape and the main building has two floors.

The name Pampus is associated with 400 years of history. From impregnable shallows of the 17th century, where ships lay off Pampus, to figurehead of the 19th-century Defence Line of Amsterdam, to 21st-century UNESCO World Heritage Site! Learn more about the history of this special island on the Fort Island Pampus website.


The 12th edition of Rondje Pampus took place on Saturday July 29, 2023. Over 400 participants swam 1, 2 or 3 laps around Fort Island Pampus in the Dutch IJsselmeer. In doing so, these open water swimmers not only delivered a special sporting achievement, but also contributed to Landschap Noord-Holland‘s research into the otter’s habitat in the Ilperveld area near Amsterdam.

Registration for the Rondje Pampus 2024 open water swimming event will be possible starting early next year. If you want to stay up to date and know when registrations open, follow us on Facebook, Instagram or Strava.

Rondje Pampus is made possible through the kind support of our partners and collaborating organizations:

If you have a question about the Rondje Pampus open water swimming event, please use the contact form on our website.

Rondje Pampus Challenge

Can’t participate in the Rondje Pampus swimming event, but still want to participate in an alternative way? Sign up for the virtual Rondje Pampus Challenge for free!

Swim a distance of 900, 1800 or 2700 meters in open water or in a swimming pool during the weekend of the Rondje Pampus swimming event. Record this swimming activity with your watch or your mobile and share the result with us on Strava. Not only will you have a chance to win one of the ten tickets for the next edition of Rondje Pampus, but you will also help to draw attention to the vulnerable nature in the IJsselmeer area.

Signing up for the Rondje Pampus Challenge is easy. Visit the Strava Club page of Rondje Pampus. Once you are on the Strava Club page click on Join Club or Become a Member. That’s all, you’re signed up for the Challenge.


Do you have a question after visiting our website? We are happy to receive an e-mail. Fill out the form below, click Submit and we’ll get back to you. If you want to stay up to date with the latest developments around Rondje Pampus, follow us on social media.

Rondje Pampus Foundation

Weesperzijde 142
1091ET Amsterdam

Chamber of Commerce: 85285528


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Partners and collaborating organizations: