1979–80 Segunda División B

The 1979–80 Segunda División B was the 3rd season of Segunda División B, the third highest level of the Spanish football league system, since its establishment in 1977. First and 2nd in each group were promoted to Segunda División, and the bottom four were relegated to the Tercera División.

Group 1
A total of 20 teams will contest the group, including 2 relegated from the Segunda División and 4 promoted from the Tercera División.

Promotion and relegation
Teams relegated from 1978–79 Segunda División Teams promoted from 1978–79 Tercera División
 * Baracaldo CF
 * Racing de Ferrol
 * Las Palmas Atlético
 * Sporting Atlético
 * Arenas de Guecho
 * CD Guecho

Teams
Teams from Aragon, Asturias, Basque Provinces, Canary Islands, Galicia, León, New Castile and Old Castile.

League table

 * Sporting Atlético was called CD Gijón until last season.

Group 2
A total of 20 teams will contest the group, including 2 relegated from the Segunda División and 4 promoted from the Tercera División.

Promotion and relegation
Teams relegated from 1978–79 Segunda División Teams promoted from 1978–79 Tercera División
 * Terrassa FC
 * Real Jaén
 * CD San Fernando
 * CD Eldense
 * UD Vall de Uxó

Teams
Teams from Andalusia, Balearic Islands, Catalonia, Extremadura, New Castile and Valencia.

League table

 * Terrassa FC was called Tarrasa CF until last season.
 * UD San Andrés was called CD San Andrés until last season.