Of the fourteen runners-up, the twelve clubs with the best PPG (points per game ratio) were also to be compulsorily promoted, but with resignations and mergers in leagues above, thirteen runners-up were promoted.
All Step 5 leagues were fixed at 20 clubs for 2018–19, but in this case there were no further relegations or reprieves.
Division One was reduced from 21 to 19 clubs after Baffins Milton Rovers, Hamble Club and Shaftesbury were promoted to the Premier Division, Fleet Spurs were transferred to the Combined Counties League, and Pewsey Vale were transferred to the Hellenic League.
Three clubs joined the division: Reserve sides are not eligible for promotion to Step 5.
All Step 6 leagues were fixed at a maximum of 20 clubs for 2018–19, but in this case there were no further relegations or reprieves.