Etar were promoted as champions of the 2016–17 Second League, sealing their title on the final day of the season with a 2–2 away draw against Nesebar, coupled with Septemvri Sofia's 0–2 away defeat to Oborishte.

[9] The promoted club replaced Lokomotiv Gorna Oryahovitsa, who suffered an immediate return to the second tier after elimination in the relegation play-offs by Montana.

Septemvri Sofia, runners-up of the 2016–17 Second League, won the play-off against Montana and return to the top flight after an 18-year absence, for the first time since the 1998–99 season.

Vitosha Bistritsa, who finished 3rd in the 2016–17 Second League, defeated Neftochimic in the play-off and won promotion to the top division for the first time in their history.

Note: From the 2016–17 season onwards, all participating clubs are required to have electric floodlights and adequate pitch conditions under the BFU and TV broadcaster's new licensing criteria.

Clubs in the domestic league can have more than one sponsorship per jersey which can feature on the front of the shirt, incorporated with the main sponsor or in place of it; or on the back, either below the squad number or on the collar area.