The league was contested by 12 teams, four less than the previous season, and played in a triple round robin format.
[2] Varaždin was promoted to the 2022–23 HNL, while Croatia Zmijavci, Osijek II, Sesvete and Opatija were relegated to 2022–23 Druga NL.
New clubs were Hrvatski Dragovoljac (relegated after single season in the top flight), relegated from 2021–22 Prva HNL and Vukovar 1991, winner of playoff between winners of five third tier leagues.
Before the start of the season, Inter Zaprešić ended up in bankruptcy and was dissolved.
Instead of them, Croatia Zmijavci, originally relegated, was returned to the league.