2018–19 Southern Combination Football League Division One

Division One remains at 18 clubs after Little Common, Langney Wanderers and Lingfield were promoted to the Premier Division, and Ringmer left the league. Four new clubs joined:


 * Alfold – promoted from Division Two
 * Littlehampton Town – relegated from the Premier Division
 * Sidlesham – promoted from Division Two
 * Worthing United – relegated from the Premier Division