12 January – It was reported that defence co-operation between the Irish and British armies is to be formalised and increased in scope when the Irish Minister for Defence and the British defence secretary sign a historic memorandum of understanding at a ceremony in Dublin by the end of January. New developments will include the Irish Army training British soldiers in peacekeeping operations, and surplus British Army equipment being donated to the Irish.[1]
14 January – A red-alert weather warning was issued by Met Éireann as Storm Rachel struck the country.[2]
18 January – Minister for Health, Leo Varadkar, revealed his homosexuality on radio, thus becoming the first openly gay government minister in Ireland.[3][4]
4 February – The ferryboat service from Dún Laoghaire to Holyhead in Wales ended after 204 years. The boat from Dublin Port to Holyhead remained in service.[5]
3 March – The Government confirmed it would lock away for 75 years any statements it received from victims of child sexual abuse (almost twice the normal length), prompting criticism from survivors.[12]
13 March – A new political party, Renua, was launched.[13]
9 April – President Higgins paid an official visit to Lebanon.[17][18]
29 April – The International Astronomical Union honoured Irish composer and harpist Turlough O'Carolan when it assigned the official name Carolan to a 24kilometre-diameter crater on the surface of Mercury. Craters on the planet are named after artists, composers, and writers.[19]
6 May – Ireland was circumnavigated by a trimaran with a seven-man crew of Omani, French, and Spanish sailors in a record-breaking 40 hours, 51 minutes, and 57 seconds, breaking the previous round-Ireland sailing record by almost four hours.[20]
15 May – Broadcaster and political editor of the TV3 television channel, Ursula Halligan, publicly declared her homosexuality and her support for a 'yes' vote for marriage for homosexuals and lesbians in the Constitutional marriage equality referendum. TV3 was thus obliged for the sake of visible journalistic objectivity to remove her from broadcast coverage of the referendum.[21][22]
26 July – The celebration of Reek Sunday, the annual climbing of Croagh Patrick, was cancelled because of dangerous weather but hundreds of people ignored warnings by the police, coastguard, and mountain rescue teams not to climb the mountain because rescues would not be possible, and even brought children.[30][31]
23 September – The Prime Minister of India, Narendra Modi, visited Dublin, where he was presented with a hurley and sliotar, and was greeted by a thousand Indian people at a gathering in Ballsbridge.[32]
2 October – The postal service, An Post, told the public not to post any mail owing to a staff dispute, then stated that staff might be dismissed if no post arrived for them to sort.[33]
10 October – Carrickmines fire: A chip pan fire swept through a halting site in Carrickmines, County Dublin, killing 11 Travellers including five adults, five children, and an unborn child.[34][35] The TaoiseachEnda Kenny ordered flags to fly at half-mast on the days of the victims' funerals.[36] A letter of condolence from Pope Francis was read to mourners at one funeral for five of the victims.[37] Hundreds of Travellers, including relatives of the victims, had an audience in the Vatican with the Pope on 26 October.[38]
12 October – The Archbishop of Dublin, Diarmuid Martin told a synod of bishops in Rome that Irish people "struggle to understand abstract moral principles" while remaining capable of understanding that people need to be happy and to belong. He also claimed that the recent debate about same-sex marriage in Ireland was conducted by laypeople in language that belonged to the Roman Catholic Church, concepts he described as "traditionally our language: equality, compassion, respect and tolerance."[39][40]
^Ó Cionnaith, Fiachra (4 March 2015). "75 years: Abuse files to be secret". Irish Examiner. Archived from the original on 9 March 2015. Retrieved 4 March 2015. The decision not to make the files publicly available [...] was put forward yesterday by Jan O'Sullivan, the education minister, and will see the files withheld for almost twice as long as State papers are normally kept.
^An Post tells customers not to send any post RTÉ News, 2015-10-02. "An Post has advised customers not to post any items with immediate effect due to industrial action....An Post said this afternoon it has not issued protective notice to staff but noted that if there is no mail coming into the system, there is no work for its employees."
^Intervention of Archbishop Martin at Synod Archdiocese of Dublin, 2015-10-12. Quote: "The referendum was debated within a social culture where people struggle to understand abstract moral principles. What they do understand is the predicament of individuals whom they wish to see happy and included. It is a very individualistic culture, but not necessarily an uncaring one. Indeed those in favour of same-sex marriage based their campaign on what was traditionally our language: equality, compassion, respect and tolerance."
^"Councillors criticise new planning powers for minister". RTÉ. "The Irish Planning Institute (IPI), which represents planners, voiced concerns about the Planning and Development (Amendment) Act 2015 which became law on 29 December – during a consultation period which began the month beforehand."
^"Ireland's men's hockey team qualify for Rio Olympics". The Irish Times. 25 October 2015. And they got over the line at 4.20am on Sunday morning when Australia secured their victory, watched on in the BBC offices in Belfast by the Irish squad.