The 2024–25 season will be the 110th season of the Isthmian League, which is an English football competition featuring semi-professional and amateur clubs from London, East and South East England.
The North Division comprises 22 teams for the first time following the introduction of play-offs at step five the previous season.
The South Central Division consists of 22 teams, 15 of which competed in the previous campaign.
The South East Division will consist of 22 teams for the first time, sixteen of which competed in the previous season.
Chatham Town were defending champions, having beaten Hashtag United in the 2023–24 season.