Regeer played in Ajax’s youth academy since 2017, when he came over from the youth of ADO Den Haag. On December 15, 2021, he made his debut in Ajax’s first team during the KNVB Cup match against Barendrecht (4-0). The youth international has so far played twice for the main squad and has scored once.
Since February 2020, Regeer has been playing for Young Ajax in the Kitchen Champion Division. He has now made sixty appearances for the reserves and has scored five times.