The Commissioners of Irish Lights (Irish: Coimisinéirí Soilse na hÉireann), often shortened to Irish Lights or CIL, is the body that serves as the general lighthouse authority for Northern Ireland and the Republic of Ireland and their adjacent seas and islands. As the lighthouse authority for the island of Ireland it oversees the coastal lights and navigation marks provided by the local lighthouse authorities, the county councils and port authorities.

It is funded by light dues paid by ships calling at ports in the Republic of Ireland, pooled with dues raised similarly in the United Kingdom. This recognises that a large volume of shipping, typically transatlantic, relies on the lights provided by Irish Lights.^{[citation needed]}

Signal fires to guide shipping have long existed. Hook Head has the oldest nearly continuous light in Ireland, originally a signal fire or beacon tended by the monk Dubhán in the fifth century.^[1] Monks continued to maintain the light until the Cromwellian conquest of Ireland in 1641.

King Charles II re-established the lighthouse in 1667. He granted a patent for the erection of six lighthouses to Robert Reading, some replacing older lighthouses,^[2] at Hook Head, Baily Lighthouse at Howth Head, Howth sand-bar, Old Head of Kinsale, Barry Oge's castle (now Charlesfort, near Kinsale), and the Isle of Magee.

In 1704 Queen Anne transferred the lighthouses around the Irish coast to the Revenue Commissioners.

The Corporation for Preserving and Improving the Port of Dublin was established under an Act of the Parliament of Ireland, the Dublin Port Act 1786 (26 Geo. 3. c. 19 (I)), entitled An Act for Promoting the Trade of Dublin, by rendering its Port and Harbour more commodious.

The Lighthouses (Ireland) Act 1810 (50 Geo. 3. c. 95) transferred responsibility for all lighthouses around Ireland's coast to the Port of Dublin Corporation, with the lighthouse operation becoming known as the 'Irish Lights Board'. The Dublin Port Act 1867 (30 & 31 Vict. c. lxxxi) reconstituted the Port of Dublin Corporation into the Dublin Port and Docks Board with responsibility purely for the port, and created the new 'Commissioners of Irish Lights' to act as the general lighthouse authority.

These acts, modified by the Irish Lights Commissioners (Adaptation) Order, 1935,^[3] remain the legislative basis for the CIL.^[4]

Irish Lights has moved its headquarters from Dublin to a purpose-built new building in Harbour Road, Dún Laoghaire.

The Commissioners of Irish Lights is a cross-border body, with its headquarters in Dublin. The current flag of the Irish Lights features lightships and lighthouses between the arms of the St. Patrick's Cross.^[7] The St. George's Cross was used until 1970.^[8] CIL vessels in Northern Ireland fly the Blue Ensign defaced with the commissioners' badge and those in the Republic fly the Irish tricolour.^[7]

The CIL operate and maintain the majority of the aids to navigation around the Irish coastline. This includes 64 lighthouses, 20 beacons and over 100 buoys. It also operates more than 100 automatic identification system transmitters, and 23 radar beacons.^[9]

• Lighthouses in Ireland
• Lightvessels in Ireland