State League 1 South Australia is the second tier state-level football (soccer) competition in South Australia, ranked third tier in the national pyramid. The league is part of the National Premier Leagues (NPL) structure implemented by Football Federation Australia in 2012. It is conducted by Football South Australia (FSA), the state's governing body. After the reforming of the South Australian football league structure in 2012, the league increased its participants from 10 clubs to 16. Football South Australia announced a restructuring of the league format in South Australia for the 2016 to 2018 seasons, moving from a 2 tiered system to a 3 tiered system with the introduction of a new 3rd division (State League 2), which reduced the participants in the now State League 1 down to 12.

A-League team Adelaide United entered their youth team in the 2015 season.