First spell at Heerenveen Casparij made her debut for
Heerenveen in the
Eredivisie at the age of 15. She made her league debut against
Twente on 6 November 2015. Casparij scored her first league goal against
Achilles '29 on 23 December 2016, scoring in the 65th minute.
VV Alkmaar After two years, she moved to
VV Alkmaar. She made her league debut against Heerenveen on 1 September 2017. She scored her first league goal against
Excelsior on 10 November 2017, scoring in the 45th minute.
Heerenveen (second stint) After a year at VV Alkmaar, she returned to Heerenveen. During her second spell, she made her league debut against Achilles '29 on 14 September 2018. She scored a
hat trick, which was also her first goals for the club during her second spell, against Achilles '29 on 27 November 2018.
Twente She joined
Twente in 2020. Casparij made her league debut against
Ajax on 6 September 2020. She scored her first league goal against
PEC Zwolle on 11 September 2020, scoring in the 82nd minute.
Manchester City On 26 July 2022, Casparij joined
Women's Super League club
Manchester City on a three-year deal. She was signed to replace
Lucy Bronze. Casparij made her league debut against
Chelsea on 25 September 2022. Along with
Rico Lewis, Casparij was named as the club's PFA Community Champions on 24 May 2024. Casparij scored and was named player of the match in a 3–0
derby win over
Manchester United in the WSL on 28 March 2026. ==International career==