[2] Later in 2004, he swam across the IJsselmeer in 4:20.58 hours, breaking the former record by almost 15 minutes to collect €50,000, which he donated to cancer research.

This result qualified him for the 10 km open water marathon race at the 2008 Summer Olympics in Beijing.

[2] There he won the gold medal on 21 August, narrowly edging out David Davies of Great Britain.

[3] He announced the end of his professional swimming career during his acceptance speech as Dutch Sportsman of the year in 2008.

[4] On 22–23 May 2017, in Amsterdam, Van der Weijden attempted to break the world record for 24 hours swimming.

In August 2018, Van der Weijden started an attempt to swim the entire track of the Elfstedentocht, a famous 200 km outdoor ice skating race in the north of the Netherlands.

[8] Eventually, with less than 10 km left to Dokkum, he had to cut his attempt short due to illness sustained in the water.

At that moment, he already had swum a distance of 163 km in 55 hours time raising over €4,3 million for cancer charities.

On 27 March 2019 Van der Weijden announced that on 21 June 2019 he would start a second attempt to swim the whole eleven-city tour.