Shoreham, who ended the season as SCFL Premier Division Champions following a points deduction to Haywards Heath Town, are promoted to the Isthmian South and swap places with Three Bridges who rejoin the SCFL after 5 seasons away following relegation from the Isthmian South.
Due to ground grading, only two teams are relegated from the SCFL Premier Division with Wick and Hailsham Town dropping down to SCFL Division One and are replaced by the promoted Saltdean United and East Preston.

The full 2017/18 SCFL Premier Division line up is:

AFC Uckfield Town
Arundel
Broadbridge Heath
Chichester City
Crawley Down Gatwick
East Preston
Eastbourne Town
Eastbourne United AFC
Hassocks
Haywards Heath Town
Horsham YMCA
Lancing
Littlehampton Town
Loxwood
Newhaven
Pagham
Peacehaven & Telscombe
Saltdean United
Worthing United

The SCFL Premier Division fixtures are due for release around 20th July and will begin on Saturday 12th August

In the SCFL Under 21 section, United are one of ten teams in the SCFL East Division and will face three new sides.
Langney Wanderers, Peacehaven & Telscombe and Saltdean United all join the league and replace Hassocks and Rottingdean Village, who both move to the West Division while Bexhill United are not running an Under 21 side this season.

The full SCFL Under 21 East Division line up is:

AFC Uckfield Town
Eastbourne Town
Eastbourne United AFC
Hailsham Town
Langney Wanderers
Little Common
Newhaven
Peacehaven & Telscombe
Saltdean United
Seaford Town

The first batch of SCFL Under 21 fixtures will be released at the same time as the Premier Division fixtures and will begin the week commencing Monday 21st August