Due to the health crisis caused by the COVID-19 pandemic in Spain, the RFEF decided for this season that there would be no games between teams from different Territorial Federations and thus not have problems with mobility restrictions. In addition, the remodeling of the RFEF national categories allows each Third Division group to have three promotion slots to the new Segunda División RFEF category, one of them through promotion play-offs.[1]
Six teams qualify from each of the Third Division groups. Four of them come from the groups called "C" or "promotion", and are those classified between the third and sixth position since the first two achieve direct promotion. The other two teams come from the groups called "D" or "play-off", and are the first two classified.[2]
As in the previous season, the promotion promotion was a single match in which the highest ranked teams has an advantage in the event of a tie. The fifth classified of group "C" faced the second classified of group "D"; and the sixth of the "C" did the same with the first of the "D". The winners of this first round faced the third and fourth teams of group "C" in the final round, deciding the third place for promotion in each of the groups.
The 36 teams that were promoted through promotion groups are included.
The numbers of years after the last promotion are referred to the last participation of the club in Segunda División B, the division that was partially replaced by the Segunda División RFEF.
