In May 2011, Eyjólfsson was chosen for the UEFA European Under-21 Championship squad. He played three times in the tournament, as the U21 national team were eliminated in the Group stage. Eyjólfsson then captained Iceland U21 for the first time, losing 3–0 against England U21 on 6 October 2011. He later captained the U21 national team in the next two matches against Azerbaijan U21. In a match against Belgium U21 on 10 September 2012, Eyjólfsson made his twenty–seventh appearances for Iceland U21, breaking a record and started the whole game, as the U21 national team lost 5–0, in what turns out to be last appearance.