From the 13th to 17th centuries, the Irish Squadron was a temporary formation assembled for specific naval campaigns, commanded by a senior officer whose title changed a number of times.

[4] In 1298, Edward I of England appointed Sir William de Leybourne as the first "Admiral of the Irish Sea", responsible for all English ships operating in that area.

[5] During the 14th century, the squadron was formed on four occasions, first in 1356 during the reign of Edward III of England to protect troop convoys against Scottish privateers.

During the Tudor period, the squadron was re-established for service in the 1539 to 1545 Anglo-Scottish Wars and again during the 1569 to 1583 Desmond Rebellions led by Sir William Wynter, who was ordered to cut off all sea routes into Ireland and seize all ships of the pending papal invasion force.

[9] During the Nine Years' War, the squadron fought at the Battle of Bantry Bay in May 1689 under the command of George Rooke who retained his position until early 1690.