The first half of the season consists of 10 teams and 100-game regular season (10 games for each of the 10 teams) begins on Saturday, October 6, 2012 and ended on Sunday, March 17, 2012.

For second half of the season clubs will be divided into two groups.

Relegation group will consist of bottom 6 teams from first half of the season.

Relegation league 5th-placed team Križevci faces the 2nd-placed Promotion league side Škrljevo in a two-legged play-off.

The winner on aggregate score after both matches will earn a spot in the 2013–14 A-1 League.