The Irish Coast Guard (IRCG; Irish: Garda Cósta na hÉireann [ˈɡaːɾˠd̪ˠə ˈkoːsˠt̪ˠə n̪ˠə ˈheːɾʲən̪ˠ]) is part of the Department of Transport in Ireland. The primary roles of the Coast Guard include maritime safety and search and rescue. The Irish Marine Search and Rescue Region (IMSRR) is the area over which the Coast Guard has responsibility. This area is bordered by the UK Search and Rescue Region.

The British Water Guard (formed 1809) and (Preventive) Coast Guard (formed 1822) extended to Ireland as part of the United Kingdom of Great Britain and Ireland. During this period the Coast Guard played revenue protection and coastal defence roles, as well as forming part of the Royal Naval Reserve. In the 1850s, the Admiralty took over the Coast Guard; officers stationed in Ireland complained that their naval career was retarded relative to those in England.

The Irish Free State was formed in December 1922, and Tom Casement (brother of Roger Casement) tried unsuccessfully to establish a new Irish coast guard. In late 1923 Casement instead became first Inspector of a new Coast Life Saving Service (CLSS). In 1927, before the Irish Naval Service had been formed, the Admiralty discussed the possibility of CLSS participation in minesweeping of the Treaty Ports. During the Emergency declared in the Second World War, the Department of Defence established a separate Coast Watch after the use of the CLSS to keep watch for belligerent ships and aircraft was vetoed by the Department of Industry and Commerce, which ran the CLSS.

The CLSS was later renamed the Coast and Cliff Rescue Service (CCRS). In 1979 there were 54 stations, 51 equipped with breeches buoys and three only with ladders for cliff rescue. A 1990 inquiry into air sea rescue chaired by retired Garda Commissioner Eamonn Doherty recommended transferring responsibility from the Irish Air Corps to a new emergency service. The then government accepted the recommendation in August 1990, and the service was established in the then Department of the Marine by minister Michael Woods in May 1991 under the name "Slánú — The Irish Marine Emergency Service" (IMES), and subsumed the CCRS. In February 2000 the name was changed to the Irish Coast Guard following the wishes of many of its personnel. The spelling "Coast Guard" (as opposed to "Coastguard") is intended to hark back to its nineteenth-century origins; His Majesty's Coastguard (HMCG) adopted the single-word spelling in 1925, after the Free State had separated from the United Kingdom.

In 2012, Fisher Associates conducted a value-for-money review of the Coast Guard and recommended closing the stations at Valentia and Malin Head. The Fisher report was criticised by Coast Guard management and reviewed by an Oireachtas committee, prompting a revised report in 2013.

The Coast Guard operates as a division of the Department of Transport under the Irish Maritime Administration (IMA). Other sections of the IMA include the Marine Survey Office and Maritime Services Division.

The Coast Guard is responsible for:

Unlike coastguard models in some other countries, in Ireland, it is not part of the Irish Defence Forces. It does however call on their assistance through the use of its Air Corps and Naval assets. Also, while in some jurisdictions fisheries patrols are the responsibility of the Coast Guard, in Ireland, these are carried out by the Irish Air Corps and Irish Naval Service and drug smuggling patrols by the Irish Air Corps, Customs, Gardaí and the Naval Service. (However, all the above government services can at any time request assistance from each other when needed).^{[citation needed]}