Simonsen played a total 55 games for the Danish national team and scored 20 goals, according to the Danish Football Association. However, some sources chose to include Simonsen's appearance in a February 1981 charity match, to tally his national team career as 21 goals in 56 games. The match was Italy vs. Europe for the benefit of the Irpinia earthquake victims. Simonsen started the game, scored a goal, and was substituted at half time as Europe won 3–0.