The club are currently members of the Eastern Counties League Division One North and play at the Royal Oak ground.

In 1935 the club became founder members of the Eastern Counties League,[8] and shared the first championship with Lowestoft Town.

They reached the final of the Amateur Cup again in 1953, but lost 6–0 to Pegasus at Wembley Stadium in front of a crowd of 100,000.

The first round was also reached again in 1961–62 and 1963–64, but the club suffered heavy defeats on both occasions, losing 5–1 at Torquay United and 8–2 at Crystal Palace.

With a third-place finish in 1976–77 they were promoted to Division One, also reaching the first round of the FA Cup again, where they lost 3–0 at home to Enfield in a replay after a 0–0 draw.

In 2002–03 Harwich were relegated to Division One of the Eastern Counties League, but finished runners-up in their first season to make an immediate return.

They were transferred to Division One North for the 2022–23 season, and went on to finish fourth in the league, qualifying for the promotion play-offs.