Iwashimizu was born inTakizawa on 14 October 1986. In 2003, she was promoted toNippon TV Beleza after developing in their youth team. She played 260 matches in theL.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 forJapan national team againstRussia.[1] She has played in the2007,2011 and2015 World Cups, winning the 2011 World Cup and winning a silver medal at the2012 Summer Olympics.[2][3] In the final minute of extra time in the2011 World Cup Final, she was sent off after receiving a red card for slide tacklingAlex Morgan. Japan would go on to win the match in the penalty shootout that followed.[4]
Iwashimizu was instrumental in Japan's victory at the2014 Asian Cup, scoring the winning goal in both the semifinal againstChina and the final againstAustralia.[5] She played 122 games and scored 11 goals for Japan until 2016.