Blagojevic has represented Australia in several international tournaments. At the 2014 FIBA U18 Oceania Tournament, Blagojevic averaged 14.4 points, 6.6 rebounds, and 1.8 assists per game. He was named to the roster for the 2015 FIBA Under-19 World Championship. In 2019, he helped Australia win bronze at the Summer Universiade in Italy. Blagojevic averaged 5.3 points and 2.0 rebounds per game in six games.