The Irish League seasons 1915/16-1918/19 were suspended due to World War I. Shelbourne competed in the Irish League and Irish Cup for the 1920/21 season but resigned from the league and cup during the season following a dispute with the Irish Football Association.
Division shown in bold when it changes due to promotion or relegation.
Top scorers shown in bold are players who finished the season as top scorer of their division.
Key to league record: Key to divisions: Key to rounds: