Cowen was invited to Team Canada's selection camp for the 2010 World Junior Championships held in Regina during December 2009. Cowen was selected to Team Canada for the event. On December 19, 2010, Cowen was named alternate captain for the 2011 Canadian junior national team to Ryan Ellis of the Windsor Spitfires, along with his fellow returnees, Brayden Schenn of the Brandon Wheat Kings and Calvin de Haan of the Oshawa Generals.