The 2012–13 División de Honor B, the XV edition, began on October 13, 2012 with the first matchday of regular season and finished on May 5, 2013 with the Promotion playoffs final.

Upon completion the regular season, the two top teams of each group play a promotion playoff consisting of semifinal and final.

The final winner is promoted to División de Honor while the loser team play the promotion playoff against the team qualified 11th in División de Honor.

Loser team will get a new chance to achieve promotion, playing a playoff against Hernani CRE for a single spot in División de Honor.

Bathco Independiente won 25–21 on aggregate and got promoted to División de Honor.