Hamhuis has played in several international tournaments at both the junior and senior levels for Canada. At the 2001 and 2002 World Junior Championships, he won a bronze and silver medal, respectively. He also appeared in four straight World Championships, winning a gold at the 2007 tournament and silver at both the 2008 and 2009 tournaments. On January 7, 2014, he was named to the 2014 Canadian Olympic Hockey Team, winning a gold medal at the 2014 Winter Olympics.