The divisions themselves are geographically separated into North-West, North-East, South-East, and South-West, covering the football clubs of their respective zones.
a.^ CSKA Sofia II officially declined to participate in the South-West Third League and was dissolved.
Maritsa Plovdiv joined the promoted teams as runners-up of the South-East group because champions Zagorets refused to participate for financial reasons.
[2] In return, four teams were relegated to the Third League: CSKA Sofia II, Spartak Pleven, Bansko and Levski Karlovo.
CSKA Sofia II was dissolved; as a result, Svoboda Peshtera (16th in 2016–17 South-West Third League) was spared from relegation to regional divisions.