When Souwer was 7 years old he started kicking. He followed his training at Ling Ho Gym in ‘s-Hertogenbosch, his trainer was John de Ling. A year later he already won all the competitions he participated in. He became Dutch, Benelux and European champion.
Souwer was 18 years old when he became world champion at three different federations. From the moment he enjoyed fame he put his shoulders under his career. In Japan he won some matches in the shooting box. His great example is Ramon Dekkers.
Souwer won the K1 MAX tournament in 2005 and 2007 in Japan. In 2006 Souwer was defeated by Buakaw Por. Pramuk giving him K.O. Hit.
On October 26, 2009, Souwer Buakaw Por beat. Poramuk in the semifinal of the K-1 World Max tournament, but lost in the final of the Italian Army Giorgio Petrosyan. Souwer is a sports instructor at SSI Souwer Sports Institute.