After Horváth's retirement in 1998, Kolonics started to focus on the singles and at the 2000 Summer Olympics he won the C-1 500 m gold medal. Afterwards he returned to doubles again, teaming up with the younger György Kozmann. The pair won a bronze medal at the 2004 Summer Olympics in C-2 1000 m, and a gold medal at both the 2006 World Championships and the 2007 World Championships in C-2 500 m. They were also to represent Hungary in both C-2 500 m and C-2 1000 m at the 2008 Summer Olympics. This would have been the fifth Olympic Games for Kolonics, who was also being considered to carry the Hungarian flag at the opening ceremony (this honour later went to kayaker Zoltán Kammerer).