Waar Is Maarten is a website dedicated to following Maarten van der Weijden during his 22-city swimming tour. It gives visitors a live view of the swim and helps them see where he is along the route. The site features an interactive map, with options to change the map display between OpenStreetMap, topographic, and satellite views. Visitors can also highlight the tour’s checkpoint locations, making it easier to follow the journey across the route.

Alongside live tracking, Waar Is Maarten encourages people to support better childhood cancer research. The website provides a direct link to a donation page, allowing visitors to contribute while following the event. Its focus is on bringing together practical route information and fundraising support in one place. The site credits Phase\Rush Media and uses Leaflet and OpenStreetMap contributors for its map experience. For supporters, viewers, and anyone interested in the swim, Waar Is Maarten offers a straightforward way to follow Maarten’s progress and take part in the campaign through a donation.