Van Rooijen made her international senior debut at the European LC Championships 1999 in Istanbul, Turkey with 4th places in both 4 × 100 m freestyle and 4 × 100 m medley relay.

In September 2000 she competed at the Sydney Olympics where she won a silver medal in 4 × 100 m freestyle relay together with Inge de Bruijn, Wilma van Hofwegen and Thamar Henneken.

After three years she returned home and found a place in Dordrecht, with Topzwemmen West-Nederland under the guidance of trainer-coach Dick Bergsma but failed to qualify for the 2004 Summer Olympics due to a severe shoulder injury.

Although she didn't meet the qualifying standards she was selected for the 2007 World Aquatics Championships in Melbourne, Australia and started in the 4 × 200 m freestyle relay which reached the final and ended third.

At the 2008 Summer Olympics she started in the heats of the 4×100 freestyle relay alongside Ranomi Kromowidjojo, Femke Heemskerk and Hinkelien Schreuder.