At the 2012 FINA Istanbul Short Course World Championships, his first major international competition, Cordes won a team gold medal and an individual bronze medal. The gold medal came his way in the 4×100 m medley relay, swimming the breaststroke leg in 57.15 (the fastest in the field). In the 100 m breaststroke, Cordes won a bronze medal with a time of 57.83.