Spanish League 2012–13 Tercera División started on 24 August 2012 and the season ended on 30 June 2013 with the promotion play-off finals.
There were 359 clubs competing in Tercera División (Third division) in the 2012–13 season, divided into 18 regional groups, accommodating between 18 and 21 clubs.
The following clubs finished as champions of their respective groups
The 18 group champion clubs participated in the Group Winners Promotion Play-off and the losers from these 9 play-off ties then proceeded to the Non-champions Promotion Play-off with clubs finishing second third and fourth.