Born in Vantaa, Pikkarainen took part in the 2008 Olympics, aged 15, she competed in the 100 m butterfly and swam 1:02.31, ranking 46th. In the 2012 Olympics she competed in the 100 and 200 metres butterfly and the 200 metres individual medley. In the 2016 Olympics she competed as part of the Finnish team in the 4 × 100 metre medley relay.