The tournament was played by 15 teams, 14 returning from the previous season and the Segunda División Profesional champions San Marcos de Arica.
The team that finished in first place at the end of the round-robin tournament earned promotion to the Campeonato Nacional for the 2021 season as Primera B champions.
Meanwhile, the teams finishing from second to sixth place played a playoff tournament for the second promotion berth, with the season runners-up having a bye to the final.
The team finishing in bottom place of this table at the end of the season was relegated to the Segunda División Profesional.
[3] On 8 June, ANFP's Council of Presidents decided to resume the league on 31 July with matches to be played behind closed doors and clubs having at least four weeks of training sessions, pending approval from the Chilean government.