Success came to the newly formed team quite quickly. In their first year of competition, they were runners-up in Division 3 of the Fingal League. In the following years, they won the Fingal League Division 1 on two occasions and the Fingal Championship once. During those years, 7-a-side tournaments were very popular and drew huge crowds to the venues. St. Marnocks were beaten in extra time by St. Margarets in the final of the Swords tournament played on a Monday in August 1930. They won the Fintan Lalor tournament, beating Erins Isle in the final. This final was played at ‘The Thatch’, where the present Catholic Church stands in Whitehall. Quite often, St. Marnocks travelled to their ‘away’ games by train. The Club Secretary would fill in a form by the Thursday before the game and the team consequently travelled at a reduced rate.