Caernarvon Athletic was formed after the First World War by players of Caernarvon United who had been demobbed. The team played initially in the North Wales Coast League and then the Welsh National League Division Two (West). In 1926, the team became professional and were immediately successful, winning the Welsh National League Division One championship in both the 1926-27 and 1929-30 seasons. In 1929 the club enjoyed an FA Cup run; reaching the second round. In 1930 the club went into liquidation and, thought they reformed briefly two years later. In 1937 Caernarfon Town FC was formed.
Source
Welsh Premiership Football League website