From the 1994-1995 to 2004-2005 season, Liga Indonesia\'s structure changed almost every year. For some seasons, there were two divisions within the top flight; for others, there were three. The number of clubs in the top flight wavered from 18-28, and seasons would last from 34-38 games. The top four clubs in each division qualified for a group stage "Final Eight Championship Playoff." Winners of the group faced off for the championship.
During the 2004-2005 season, 18 clubs comprised the Indonesian top flight. A season lasted 34 games, in which each club played against each other on a home-and-away basis. The three teams at the bottom of the table are relegated into Division Satu, the second level of the Indonesian league system, while the three teams of Division Satu that won promotion replace them. The top two finishers in the league qualify for the AFC Champions League.
Starting with the 2003-2004 season, the championship was decided a double round-robin league system involving the top clubs of each division. Beginning with the 2005-2006 season, 28 clubs will comprise Liga Indonesia. Clubs compete in two divisions of 14 clubs each. Each club plays against each other on a home-and-away basis.
The league\'s popularity has grown so much that the 2006-2007 season will see another big expansion of the league from 28 to 36 clubs with both divisions comprising 18 clubs each.
In 2008, 18 top ranked clubs in the previous Premier Division were \'promoted\' to a new highest level of competition, the Indonesia Super League, and the rest stayed in the same division. The PSSI examined those 18 clubs for their readiness to join the ISL, considering many aspects, like the stadium, financial condition and other requirements for full professional football clubs.[3]
Promotion and relegation rules for the top few levels:
1. Liga 1 (level 1, 18 teams): The Bottom three teams are relegated.
2. Liga 2 (level 2, 60 teams): The champions, runner-up and third placed are promoted.
3. Liga 3 (level 3): The Champions and other best team are promoted.