Manthey played with teams internationally in France and most recently in Iceland. She played with the Seattle Sounders Women for the 2012 season. Previously, Manthey played in 61 matches for Fortuna Hjørring in Denmark. Manthey helped Fortuna Hjørring to the Danish Championship in 2009, 2010, and 2011. She played Division Isoccer for University of Colorado and College of Charleston. While with College of Charleston she was an All-Southern Conference selection. She scored 14 goals and 6 assists in 21 games for the 2008 season with the Cougars.