The under-21 competition rules insist that players must be 21 or under at the start of a two-year competition,so technically it is up to an U-23 competition.To be eligible for the Greece National Team, all the football players must hold Hellenic (Greek) nationality and comply with the provisions of Article 15 of the regulations governing the Application of FIFA Statutes. A list of 35 football players must be submitted to the UEFA administration 30 days before the European Under-21 Football Championship opening match. Only 22 of the 35 players listed are authorised to take part in the final tournament and 3 of them must be goalkeepers.
As long as they are eligible, players can play at any level, making it possible to play for the U-21s, senior side and again for the U-21s, as Sotiris Ninis has done recently. It is also possible to play more than one country at youth level or different at youth level and different at senior level (providing the player is eligible). But a football player can represent only the senior national team that capped him first.
Also in existence are national teams for Under-20s (for non-UEFA tournaments), Under-19s and Under 17s.Greece also has a women's national team.