It serves at the behest of the Defence Forces and Government of Ireland, operating internally and overseas, and reports directly to the Chief of Staff.

The 2015 White Paper on Defence announced that the strength of the ARW would be considerably increased due to operational requirements at home and overseas.

[8] The unit has served abroad in a number of international peacekeeping and peace enforcement missions including in Somalia, East Timor, Liberia, Chad, and Mali.

Na Fianna were purportedly expert warriors, so the addition of the word Fiann before Óglaigh denotes an elite element to the unit.

[4] In the late 1960s, the Defence Forces established 'Special Assault Groups' (SAG) in the Army to meet security challenges on the border with Northern Ireland.

[22] Following an assessment of the SAG, and Rangers receiving training from the M-Squadron, an elite counter-terrorism (CT) branch of the Royal Netherlands Marine Corps,[23] in 1978 it was decided to consolidate the Rangers into a new special forces unit with a counter-terrorist capability following an increase in international and national terrorism, such as the 1972 Munich massacre in Germany (then West Germany) and a number of hostage-takings by the Provisional IRA (such as the Balcombe Street siege).

[26] On 16 January 2022, there were recommendations made for some ARW operators to be based in Cork to work alongside their colleagues in the Naval Service in improving its maritime anti-terrorism capabilities.

[33] Training is carried out nationwide at a number of Department of Defence properties, including Lynch Camp in Kilworth, County Cork.

[44] The ARW is on a 1-hour alert for anti-terrorist operations to deploy anywhere on land in the Republic of Ireland using Air Corps aircraft and up to 200 miles out to sea via the Naval Service vessels.

[54] Candidates must be serving members of the Permanent Defence Forces (PDF) from any of the three branches (Army, Air Corps or Naval Service).

[56] Officer and senior NCO candidates are subjected to separate, rigorous scrutiny of their planning and decision-making skills to determine their suitability.

[39] The ARW has its own purpose-built tactical training facilities, including shooting ranges, kill houses and various urban and rural settings.

[76] Rangers have seen active service in a number of peacekeeping missions around the world with the United Nations, European Union (EU) and Partnership for Peace (PfP) of the North Atlantic Treaty Organization (the Republic of Ireland is not a member of NATO, due to its policy of military neutrality).

[69] The ARW's first deployment overseas was in Somalia in 1993 as part of UNOSOM II where a number of teams joined the United States-led peacekeeping coalition tasked with imposing a ceasefire in the Baidoa region.

[96] In June 2019, Dáil Éireann approved sending an ARW Task Unit and staff officers to the UN Multidimensional Integrated Stabilization Mission in Mali (MINUSMA) in intelligence and operational roles, on 4-month rotations for two years.

[101] In February 2020, three ARW personnel were injured when an IED blast hit the armoured patrol vehicle they were travelling in, 70 km east of Gao.

[106] Following negotiations with Irish, British and American government representatives, Rory Carroll was released unharmed days later and returned safely to Ireland.

[108][109] With the fall of Muammar Gaddafi in 2011 and the Libyan Civil War, the ARW, Air Corps and other Defence Forces assets were deployed in order to evacuate upwards of 115 Irish citizens from the country, mainly via the capital Tripoli.

[110] It was reported at the time that Irish officials printed fake boarding passes in order to bypass "tight" security at Tripoli airport, where authorities refused to allow a large number of aircraft to land or take off.

In October 2019 it was reported that the ARW were deployed to the Syrian border to extract Lisa Smith - a former Irish Army soldier who converted to Islam before fleeing Ireland to join ISIS - and her two-year-old child in a Non-Combatant Evacuation Operation (NEO) after the 2019 Turkish offensive into north-eastern Syria resulted in Kurdish-held ISIS prisoners escaping, including Smith, although the Defence Forces or Irish government did not confirm this.

[114] On 23 August 2021 in the aftermath of the Fall of Kabul to the Taliban, Minister for Foreign Affairs and Defence Simon Coveney approved the deployment of an Emergency Consular Assistance Team (ECAT) comprising ARW personnel and a small team of DFA diplomats to Hamid Karzai International Airport in Kabul in order to evacuate Irish citizens.

[120][121] In 2012, it was reported that the ARW could deploy 30 Rangers in the Gulf of Aden, subject to Government, Dáil and UN approval ("triple-lock"), to protect international shipping lanes against Somali pirates as part of the EU's Operation Atalanta.

[123] The ARW was chosen to spearhead the special operations task group (SOTG) for the EU Battlegroup rapid reaction force based in Germany, deploying in late 2019.

[127] In May 2011, the unit had a major role in protecting Queen Elizabeth II on her state visit to Ireland,[128] where "viable" assassination attempts by dissident republican terrorists were prevented.

From January to July 2013, the wing formed part of the security apparatus for the Presidency of the Council of the European Union, held by Ireland for six months, which included supplying sniper and spotter teams.

[134] In the early morning of 26 September 2023, an ARW Maritime Task Unit was involved in the storming of MV Matthew, a Panamanian-registered bulk cargo vessel, off the coast of Cork in what was described as an "opposed boarding operation".

[135] The ship had crossed the Atlantic from Venezuela; approximately 2,200 kilograms of cocaine with an estimated street value of €157 million were found hidden on board the next day, in the largest seizure of illegal narcotics in Irish history.

Sergeant Derek Mooney, aged 33, of Blackrock, Dublin, died after the Land Rover Defender he was driving in a convoy overturned due to poor road conditions, 40 km south of Monrovia, Liberia on 27 November 2003.

[141] Sgt Kevin Mayne (1987) and RQMS Patsy Quirke (1998) also lost their lives while serving in the unit,[142] however no details regarding the cause of their deaths are publicly available.

In Paul O'Brien and Wayne Fitzgerald's book Shadow Warriors, it states "four operatives losing their lives while on active service" with the ARW, however, their names and details are omitted at the request of the Irish Defence Forces.