In 1909 the Oystermen joined the original Kent League, where they played until it folded in 1959, winning the Division Two title three times. They also lifted the Kent Amateur Cup (now Kent Senior Trophy) in 1929. After the collapse of the Kent League, the club played for a while in the Aetolian League, but this meant long trips to play London teams as opposed to the earlier money-spinning East Kent derbies, and this was a period of financial struggle for the club, which dropped into the amateur leagues for a number of years.