At first, it was possible to play for different national teams, but in 2004, FIFA enacted new rules on the international eligibility of players.

As the world football governing body, FIFA is responsible for maintaining and implementing the rules that determine whether a football player is eligible to represent a particular country in officially recognised international competitions and friendly matches.

At first FIFA allowed a player to represent any national team, as long as the player held the citizenship of that country. However, in reaction to the growing trend towards naturalisation of foreign players in some countries, FIFA in 2004 enacted a significant new ruling that requires a player to demonstrate a "clear connection" to any country they wish to represent and uses its authority to overturn results of competitive international matches that feature ineligible players.

The new rulings which went into effect as from January 2004 permits a player to represent one country at youth international level and another at senior international level, provided that the player applied before their 21st birthday. This ruling explicitly stated that, in such scenarios, the player must have at least one parent or grandparent who was born in that country, or the player must have been resident in that country for at least two years. The residency requirement for players lacking birth or ancestral connections with a specific country was extended from two to five years in May 2008 at FIFA's Congress as part of Blatter's efforts to preserve the integrity of competitions involving national teams.

Article 17 of FIFA statutes related to the acquisition of a new nationality, states that "any player who assumes a new nationality and who has not played an international match in an official competition of any category or any type of football for one Association, shall be eligible to play for the new representative team only if he was born on the territory of the relevant association or his biological mother or biological father was born on the territory of the relevant association."

However, this rule was further modified during the 59th FIFA congress in the Bahamas with the age limit which stood at 21, completely scraped off upon a proposal from the Algerian federation. Henceforth, a player with double nationality can decide to change selections at any age if he has played only in lower categories in his first country. Only players who have played for senior national teams can no longer change their nationality.