Following her senior debut in March 1996, Österberg Kalmari represented the Finland women's national football team 130 times, scoring 41 goals. She is the all-time leading goalscorer of the national team. In 2005, Österberg Kalmari played in the finals of the 2005 European Championships in North West England. Finland reached the semi-finals, which remains her nation's best achievement in women's football.