She won a silver medal in the 2018 European Championships in the 1500m. On 3 March 2019, she won a bronze medal in the 1500 metres at the 2019 European Athletics Indoor Championships. In Bern, Switzerland, 24 July 2020, Mageean became the first Irish woman to run sub-two minutes for the 800m, adding to her mile and 1500m national records.