As a junior Wallin participated at the 2002 World Junior Speed Skating Championships. Wallin represented her nation at four World Sprint Speed Skating Championships for Women and at two World Single Distance Speed Skating Championships. She participated at the World Sprint Championships in 2006 (finishing 29th overall), 2007 (finishing 23rd overall), 2008 (finishing 30th overall) and in 2009 (finishing 26th overall). At the 2007 World Single Distance Speed Skating Championships she competed in the 500 metres event (17th) and in the 1000 metres event (22nd). Two year later at the 2009 World Single Distance Speed Skating Championships she competed in the 500 metres event. She also competed at other international competitions, including at ISU Speed Skating World Cups.