In their debut season, 1999–2000, Sudbury finished in third place in the Eastern Counties League Premier Division. The following five seasons all resulted in Sudbury winning the Premier Division title – a league record. Sudbury did not take promotion at any of these opportunities, despite being entitled to. In this period Sudbury had a series of good performances in national cup competitions. In 2000–01 the club reached the first round of the FA Cup, where they were beaten 6–1 by Darlington. They reached the semi-final of the 2001–02 FA Vase, before being knocked out by Tiptree United. The following three seasons saw Sudbury reaching the final each year (a Vase record), but being defeated every time, by Brigg Town in 2003 (after which Martin left the club and was replaced by Gary Harvey), Winchester City in 2004 and Didcot Town in 2005. However, the club did win the Suffolk Premier Cup three times, in 2001–02, 2002–03 and 2003–04.