The competition began on 2 February 2018 and ended on 1 December 2018.
The team that finished in first place at the end of the round-robin tournament earned promotion to the Campeonato Nacional for the 2019 season.
Meanwhile, the teams finishing from second to sixth place played in 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 at the end of the season was relegated to the Segunda División Profesional.
Cobresal won 4–3 on aggregate and earned promotion to the Primera División.