Kosterink played for Run '71 Oldenzaal, Tex Town Tigers, Gulf Coast CC and since 2007 for Sparks Haarlem. She is an outfielder who bats and throws right handed. She competes for the Dutch national team since 2005. In 2007 she hit the most home runs in the Dutch Softball Hoofdklasse and during the European Championships that year she was named as Best Outfielder of the tournament. She is part of the Dutch team for the 2008 Summer Olympics in Beijing.