Duggan's first International Ice Hockey Federation (IIHF) tournament with the American senior women's team was the 2007 IIHF Women's World Championship held in Manitoba, Canada. Duggan recorded a single assist for the Americans at the tournament, as they took home the silver medal. At the 2009 tournament, the American team captured its second straight gold medal by defeating Canada in the final. Duggan scored two goals in the tournament, finishing tenth on the American team in scoring.