The 2012–13 season (35th edition) of BAI Basket kicked off on November 16, 2012, with 10 teams playing the regular season in a double round robin system.

The 5 best teams qualified for group A and the last five, group B in an intermediate stage, in which each group will play in a double round robin, at the end of which the best four teams of group A are playing the final four for the title in a round robin system at four rounds.

The relegated team from group A in the intermediate stage joined the best three teams of group B from the intermediate stage to play for the 5th-8th place classification whereas the last two teams will play for the last two.

Primeiro de Agosto won the championship after finishing the final four with a 9–3 record.

As the group winner, Primeiro de Agosto is awarded a bonus point for the final four.