Further victories in the Peterborough Senior Cup came in 1966–67, 1971–72 and 1986–87, whilst the league title was won in 1973–74, 1978–79.

Following back-to-back titles in 1986–87 and 1987–88, the club became founding members of the new Division One of the Eastern Counties League in 1988.

Although they beat Norwich CBS 1–0 in the semi-finals, they lost 3–1 to Harleston Town in the final.

The following season saw them finish as runners-up in the division, this time winning the promotion play-offs by beating Whittlesey Athletic 4–1 in the semi-finals and Harwich & Parkeston 4–0 in the final to earn promotion to the Premier Division.

Downham won the Norfolk Senior Cup for a third time in 2023–24, beating Gorleston 4–2 in the final.