Welsh sides that play in English leagues are eligible, although since the creation of the League of Wales there are only six clubs remaining: Cardiff City (the only non-English team to win the tournament, in 1927), Swansea City, Newport County, Wrexham, Merthyr Town and Colwyn Bay. In the early years other teams from Wales, Ireland and Scotland also took part in the competition, with Glasgow side Queen's Park losing the final to Blackburn Rovers in 1884 and 1885 before being barred from entering by the Scottish Football Association. In the 2013–14 season the first Channel Island club entered the competition when Guernsey F.C. competed for the first time.

May Welsh clubs enter the competition?