As a member of the junior national teams of Spain, Hernangómez played at the 2012 Albert Schweitzer Tournament, where he was named to the All-Tournament Team. He also played at the 2011 FIBA Europe Under-18 Championship, where he won a gold medal, and at the 2014 FIBA Europe Under-20 Championship, where he won a silver medal, and was named to the All-Tournament Team.