Klaas-Erik Zwering (born 19 May 1981) is a former Dutchswimmer and an Olympic medalist. He is currently studying MBO entrepreneurship as he trained in Eindhoven with the PSV Eindhoven swim club. His personal coach was Jacco Verhaeren, who is also coach for Dutch swimming phenom Pieter van den Hoogenband.
In 2001 at the FINA World Championships in Fukuoka, Japan, Klaas-Erik was a member of the silver medal winning 4×100 meter freestyle relay team. Later, along with teammates Pieter van den Hoogenband, Johan Kenkhuis and Mitja Zastrow, Zwering won his first Olympic silver medal in the 4×100 meter freestyle relay in the 2004 Olympic Games in Athens, Greece. Afterwards he retired.[citation needed]