[1] After the abandonment of the previous two seasons due to the COVID-19 pandemic,[2][3] a number of promotions were decided on a points per game basis over the 2019–20 and 2020–21 seasons.
The Premier Division was reduced to 19 clubs from 21 after Plymouth Parkway were promoted to the Southern League, and Bradford Town, Chipping Sodbury Town, Cribbs, Hallen, Roman Glass St George and Westbury United were transferred to the Hellenic League.
Odd Down requested demotion to Division One, which the league accepted.
Prior to this season, Bridgwater Town merged with women's club Yeovil United, forming Bridgwater United.
The First Division was increased from 20 clubs to 21 after Ashton & Backwell United were promoted to the Premier Division, and Calne Town and Corsham Town were promoted and transferred to the Hellenic League Premier Division.