Iwashimizu was born in Takizawa on 14 October 1986. In 2003, she was promoted to Nippon TV Beleza after developing in their youth team. She played 260 matches in the L.League until 2017. She was elected to the league's Best XI for 12 years in a row (2006-2017).
On 18 February 2006, when Iwashimizu was 19 years old, she debuted for Japan national team against Russia.[1] She has played in the 2007, 2011 and 2015 World Cups, winning the 2011 World Cup and winning a silver medal at the 2012 Summer Olympics.[2][3] In the final minute of extra time in the 2011 World Cup Final, she was sent off after receiving a red card for slide tackling Alex Morgan. Japan would go on to win the match in the penalty shootout that followed.[4]
Iwashimizu was instrumental in Japan's victory at the 2014 Asian Cup, scoring the winning goal in both the semifinal against China and the final against Australia.[5] She played 122 games and scored 11 goals for Japan until 2016.
