Eerik Haamer gained his first international experience at the European Youth Olympic Festival (EYOF) 2017 in Győr , Hungary , where he finished fifth with a jump of 4.60 m. In the following year he won the bronze medal at the U18 European Championships there with a height of 5.10 m in the first attempt behind the Norwegian Pål Haugen Lillefosse (5.46 m) and Baptiste Thiery from France (5.30 m). He also qualified for the Youth Olympic Games in Buenos Aires , where he finished fourth. In 2019 he finished seventh at the U20 European Championships in Borås with 5.11 m.
In 2020 , Haamer was Estonian champion in the outdoor pole vault and in 2019 in the hall.