- On 22 May 2019 Kaliakra 1923-Levski 2012 (Kavarna) is renamed to Kaliakra 1923. The name change comes into force with the start of this season.
- On 7 August 2019 Lokomotiv (Ruse) withdraws due to organizational and financial reasons. ZS Varna is to confirm their withdrawal from the group.
- Shumen 2007 (Shumen) plays its home games at the "Panayot Volov" st. in Shumen.
- On 20 November 2019 Kaliakra 1923 (Kavarna) is removed from the group for a third no-show without an excusable reason. Its results are annulled.
- On 4 February 2020 Hitrino (Hitrino) withdraws. Its results still count and its opponents until the end of the season are awarded 3:0 wins.
- On 17 July 2019 newly promoted Chiko Bunara (Byaga) declines participation in Treta liga due to financial constraints. ZS na BFS - Sofia decides that the group remains with 17 teams for this season.
- Kyustendil (Kyustendil) plays its home games at the "Osogovo" st. in Kyustendil.
- On 14 June 2019 STK removes Vereya (Stara Zagora) from the group, due to a decision by the Licensing commission from 4 June 2019 g., which entered into force on 13 June 2019. Vereya can enter in Yugoiztochna Treta liga, but doesn't register for participation by the deadline - 13 July 2019.
- Dimitrovgrad 1947 (Dimitrovgrad) plays its home games at the "Minyor" st. in Dimitrovgrad.
- Maritsa 1921 (Plovdiv plays its home games at the "Maritsa" st. in Plovdiv.
- Rozova dolina (Kazanlak) plays its home games at the "Sevtopolis" st. in Kazanlak.
- Haskovo 1957 (Haskovo) plays its home games at the "Haskovo" st. in Haskovo.
- Chernomorets 1919 (Burgas) plays its home games at the "Chernomorets" st. in Burgas.
- On 11 September 2019 Sokol (Markovo) is deducted 3 points for a no-show without an excusable reason.
- On 21 January 2020 FK Haskovo 1957 (Haskovo) withdraws. Its results still count and its opponents until the end of the season are awarded 3:0 wins.