It ended on 19 January 2013 when Stade Français hosted competition newcomers London Welsh,[3] followed by the knockout stages culminating in the final at the RDS Arena in Dublin on 17 May 2013.

[5][6][7] Gernika Rugby Taldea represented Spain despite finishing just 5th in the División de Honor.

Valladolid won the División de Honor, and the championship playoff, but turned down the opportunity to play in the Challenge Cup due to economic factors.

Teams that did not qualify for the 2012–13 Heineken Cup were ordered into four tiers according to the European Rugby Club Ranking.

The brackets show each team's European Rugby Club Ranking at the end of the 2011–12 season.