SNL) was divided into four regional groups with a total of 38 participating clubs.
The group winners played a two-legged play-off for promotion to the Slovenian Second League.
Zarica Kranj withdrew and were replaced by Žiri one week before the start of the season.
[2] A total of ten teams competed in the league, including nine sides from the 2017–18 season and one team relegated from the 2017–18 Slovenian Second League (Veržej).
A two-legged play-offs between the group winners for promotion to the Slovenian Second League.