The 2003–04 season was the 101st in the history of the Southern League. The season began on 16 August 2003 and ended on 8 May 2004 with the play-off finals.
At the end of the season the National League System was reorganised. A new Conference North and South was to be formed from the top teams in the Northern Premier League, Southern League and Isthmian League as follows:
From the Southern League:
Dorchester Town qualified for the Conference South.
Source:
Source:
Redditch United qualified for the Conference North