1986–87 Isthmian League

The 1986–87 season was the 72nd season of the Isthmian League, which is an English football competition featuring semi-professional and amateur clubs from London, East and South East England. League consisted of three divisions. The Second Division was divided into two sections.

Wycombe Wanderers won the league and returned to the Conference at the first attempt.

Premier Division
The Premier Division consisted of 22 clubs, including 19 clubs from the previous season and three new clubs:
 * Bromley, promoted as runners-up in Division One
 * St Albans City, promoted as champions of Division One
 * Wycombe Wanderers, relegated from Alliance Premier League

Division One
Division One consisted of 22 clubs, including 16 clubs from the previous season and six new clubs:

Two clubs relegated from the Premier Division:
 * Billericay Town
 * Epsom & Ewell

Two clubs promoted from Division Two North:
 * Kingsbury Town
 * Stevenage Borough

Two clubs promoted from Division Two South:
 * Bracknell Town
 * Southwick

Division Two North
Division Two North consisted of 22 clubs, including 16 clubs from the previous season and six new clubs:


 * Aveley, relegated from Division One
 * Chesham United, relegated from Division One
 * Collier Row, joined from the London Spartan League
 * Harlow Town, relegated from Division One
 * Hornchurch, relegated from Division One
 * Wivenhoe Town, joined from the Essex Senior League

Division Two South
Division Two South consisted of 21 clubs, including 18 clubs from the previous season and three new clubs:


 * Chalfont St Peter, transferred from Division Two North
 * Chertsey Town, joined from the Combined Counties League
 * Harefield United, transferred from Division Two North