While Clarkson is a NCAA Division III school, both the men's and women's ice hockey teams compete in Division I, with both teams playing in the ECAC. The men's team is a traditional power in the ECAC. They have won 5 ECAC Tournament Championships, most recently in 2007. Clarkson's most recent NCAA tournament was as the number three seed in the 2008 NCAA East regional, where they knocked off St. Cloud State 2–1 to advance to the second round. The Golden Knights were then defeated by national number one seed, Michigan, 2–0. The women's team is far younger, beginning play in 2003, than the men's team, although they too have become an ECAC power. The team has appeared in every tournament since entering the ECAC in 2004 and have appeared in three NCAA tournaments, most recently winning the 2018 edition, the third NCAA title won by the school, the third NCAA ice hockey title won by a school in St. Lawrence County, and the third Division I NCAA championship won by a school from the North Country. Other Division III varsity teams compete in the Liberty League conference and include baseball, men's and women's basketball, men's and women's cross country, men's golf, men's and women's lacrosse, men's and women's soccer, softball, men's and women's swimming, and women's volleyball. The men and women's alpine skiing and nordic skiing teams compete in the MacConnell Division of the Eastern Collegiate Ski Conference, within the United States Collegiate Ski and Snowboard Association. They are top contenders almost every year within their division and even conference, and have consistently qualified for the annual USCSA National Championships numerous times. Other non-varsity clubs include men's and women's ice hockey, men's lacrosse, men's and women's rugby union, men's soccer, men's bowling, combined men's and women's crew, and ultimate frisbee. Clarkson's combined men's and women's clubracquetball team won the Division II title at the USRA National Tournament in 2005. In 2010, the school started a club football team. "The Golden Knight" is the university's hockey mascot, which can be seen at hockey games waving the Clarkson flag.
