Isthmian League Division One South 2016-17

On 12 May 2016 league constitution was announced.

Division One South will feature five new clubs:
 * Cray Wanderers, transferred from Division One North
 * Godalming Town, transferred from Southern Football League Division One Central
 * Greenwich Borough, promoted from Southern Counties East League
 * Horsham, promoted from the Southern Combination League
 * Lewes, relegated from the Premier Division