Kammala jumla mai zuwa: Lountzis shi ne kyaftin din 'yan wasan Girka na kasa da shekaru 16 a gasar FIBA ta Turai a shekara ta 2014. Ya kuma taka leda tare da 'yan wasan matasa na Girka a gasar zakarun Turai.
2015 FIBA Under-19 gasar cin kofin duniya, 2015 FIBA Turai Under-18 Championship, inda ya lashe lambar zinare, da kuma a karo na biyu 2016 FIBA Turai Under-20 Championship Division B, inda ya lashe lambar tagulla. Ya kuma buga a 2017 FIBA Turai Under-20 Championship, inda ya lashe lambar zinare.