In 2006 van Aggele qualified for the European LC Championships 2006 but didn't start because he had trained to hard and was too tired to compete. In Helsinki he won his first international medal with the Dutch relay team in 4×50 m freestyle finishing 3rd. At the World LC Championships 2007 he reached a 10th place in the 50 m breaststroke as best result. At the national championships in June he nominated himself for the 200 m individual medley in Beijing 2008. At the end of the year he confirmed his nomination and qualified for the games at Dutch Open Swim Cup. One week later he won a bronze medal with the 4×50 m medley team at the European SC Championships 2007 in Debrecen.
In 2008 his first big tournament of the year was in his home country, the European LC Championships 2008 which was held in Eindhoven. After a disappointing start of the tournament, he came back strong breaking the 100 m butterfly national record of Joris Keizer bringing it to 52.20 and finishing 4th in the final. At the last day of the tournament he finished 4th again this time in the 4×100 medley relay together with Nick Driebergen, Thijs van Valkengoed and Mitja Zastrow swimming a national record in 3:37.00. A few weeks later he won a silver medal at the World SC Championships 2008 in Manchester with the 4×100 m freestyle team. He also reached 3 individual finals in the 50 and 100 m breaststroke and the 100 m individual medley.
The 2008 Summer Olympics were a big disappointment for van Aggele; he was eliminated in the heats of the 100 m butterfly, 200 m breaststroke and the 200 m individual medley. One month after the Games he announced to join Swimclub AZ&PC and started training under the guidance of Fedor Hes, who helped him already in his Beijing preparations.