The 2009–10 season was the 107th in the history of the Southern League, which is an English football competition featuring semi-professional and amateur clubs from the South West, South Central and Midlands of England and South Wales. At the end of the previous season Division One Midlands was renamed Division One Central.

Premier Division

The Premier Division consisted of 22 clubs, including 17 clubs from the previous season and five new clubs: Farnborough won the Premier Division and were promoted to the Conference South, while play-off winners Nuneaton Town achieved the second promotion in two seasons after club reorganization to return in Conference. Clevedon Town and Rugby Town were the only clubs relegated this season, while Merthyr Tydfil were expelled from the league after failing to meet a FA deadline to give assurances that they could trade effectively during 2010–11, liquidated and reborn under the name Merthyr Town three divisions below Southern League Premier Division. Tiverton Town and Hemel Hempstead Town were reprieved from relegation due to clubs higher up the pyramid folded and demoted.

League table

Play-offs

Results

Stadia and locations

Division One Central

The division was renamed at the end of the previous season and consisted of 22 clubs, including 17 clubs from previous season Midland division and five new clubs: Bury Town won the division in their second season in the Southern League and returned to the Isthmian League to take a place in Premier Division, while play-off winners Chesham United went back to Southern League Premier Division after three seasons of absence. Aylesbury United finished bottom of the table and were relegated to the lower leagues along with Rothwell United who resigned from the league at the end of the season. Thus, Barton Rovers finished second bottom were reprieved from relegation.

League table

Play-offs

Results

Stadia and locations

Division One South & West

Division One South & West consisted of 22 clubs, including 16 clubs from previous season and six new clubs: Windsor & Eton won the division and got a place in Premier Division along with play-off winners Cirencester Town, who returned there at the second push. A.F.C. Hayes finished second bottom but were reprieved from relegation due to higher league clubs problems. Thus, Bracknell Town, finished bottom of the table, were the only club relegated to the lower league this season.

League table

Play-offs

• after extra time

Results

Stadia and locations