The following is a timeline of the COVID-19 pandemic in Ireland in 2020.

Timeline January 2020 27 January – The National Public Health Emergency Team (NPHET) for COVID-19 was created to co-ordinate the national response to the pandemic.

February 2020 5 February – The Coronavirus Expert Advisory Group—a subgroup of NPHET chaired by Dr Cillian de Gascun, the UCD-based Director of the National Virus Reference Laboratory – met for the first time in Dublin. 29 February The first confirmed case in Ireland was announced involving a male student from the east of the country, who had arrived there from Northern Italy. Ireland subsequently entered the Containment Phase. Authorities shut a secondary school linked to the case as a precautionary measure. The State did not name the school involved, but—shortly afterwards—the Irish Examiner'''s Political Editor, Daniel McConnell, tweeted a copy of the letter it had sent to parents informing them it would close.

March 2020 3 March – A second case was confirmed of a female in the east of the country who had been to Northern Italy. She had no contact with the first case. 4 March – Four more cases were confirmed, two females and two males in the west of the country who travelled from Northern Italy, bringing the total to six. 5 March – Seven more cases were confirmed, bringing the total to 13. Four of the cases were related to travel from Northern Italy—four males from the east of the country—one of these four cases was connected to Trinity College Dublin. Two of the seven cases were associated with close contact with a confirmed case—two females in the west of the country. One of the seven cases was a male in the south of the country who had no history of travel abroad. 6 March It was reported that more than 60 staff at Cork University Hospital would have to self-isolate following a case of community transmission of COVID-19 at the hospital. The same day brought confirmation of five more cases, bringing the total in the country at that time to 18. 11 March An elderly patient in Naas General Hospital in County Kildare (south-west of the country's capital city, Dublin) became Ireland's first fatality from the virus; nine new cases were announced. This brought confirmed cases to 43. Cork University Hospital discharged a patient who had been admitted for coronavirus disease after they made a full recovery. 12 March 27 new cases were confirmed, bringing the total cases in the country to 70. In response to the increase of cases, Taoiseach Leo Varadkar announced the closure of all schools, colleges and childcare facilities until 29 March. The announcement, which came one day after the World Health Organization formally declared that the outbreak was pandemic, also marked Ireland's movement from the Containment Phase in its strategy to combat the spread of the virus (a strategy which the Department of the Taoiseach had reaffirmed just three days earlier) towards the Delay Phase. 13 March – Following the introduction of restrictions on social gatherings, RTÉ One aired the first edition of The Late Late Show to go ahead without a studio audience. 14 March – 39 new cases were confirmed and another death announced of a man in the East of the country with underlying medical conditions. This brought the total cases to 129, with 2 deaths in total. 15 March 40 new cases were confirmed. The total number of cases stood at 169 with 2 deaths. The Government of Ireland ordered bars and public houses to close and advised against house parties. 18 March 74 new cases were confirmed, bringing total cases in the country to 366 with 2 deaths. More detailed information about hospital statistics, age range affected, how COVID-19 was spreading, healthcare workers and cases by county was published by the National Public Health Emergency Team starting on this day. It showed that the virus was present in 23 of the 26 counties, with Laois, Leitrim and Monaghan the only three yet to record a case. 19 March – 191 new cases were confirmed, bringing total to 557. 1 new death was recorded, bringing the total to 3 deaths. The woman died in an isolation ward in St Vincent's Hospital. Her daughter later spoke to the media and urged the public to protect themselves from the virus. 20 March – 126 new cases were reported, bringing the total to 683. It was also confirmed that the virus had since infected Laois and Leitrim, leaving Monaghan as the last of the 26 counties. 22 March – 121 new cases were announced, bringing the total to 906. A fourth death was also announced, bringing the total number of deaths to 4. The man, who died at the Mater Hospital, was musical director of a choir in Dublin and former Head of Vocal Studies at the Royal Irish Academy of Music. 23 March – A further 219 cases and 2 more deaths were announced, bringing the totals to 1,125 cases and 6 deaths. Of those then diagnosed, 208 were health care workers. 26 March 255 cases and 10 deaths were confirmed, bringing the total number of confirmed cases to 1,819, and the total number of deaths to 19, more than double the previous day's total. According to Chief Medical Officer Tony Holohan, most of the deaths occurred in "institutional settings", i.e. hospitals and nursing homes. At this point, deaths began to accelerate rapidly. 27 March 302 new cases as well as 3 new deaths brought the total number of confirmed cases and deaths to 2,121 and 22, respectively. Among the deaths was the country's first healthcare fatality, who was based in the east. Taoiseach Leo Varadkar announced a national stay-at-home order with a series of measures which he summed up as: "Stay at Home" (subject to certain exemptions). Merrion Street described it as "a more intensive phase in our response to COVID-19". The measures, which coincided with an escalating death toll, were also a response to increased reliance on intensive care units (ICUs) to treat critically ill patients, and an attempt to lower this number before capacity was reached. 31 March – 325 cases and 17 deaths were reported, bringing the total number of confirmed cases and deaths to 3,235 and 71, respectively.

April 2020 1 April An additional 212 cases and 14 deaths were reported, bringing the total number of confirmed cases to 3,447, and the total number of deaths to 85. It was also announced that Chief Medical Officer Tony Holohan, who displayed signs of illness during the previous evening's news conference, had entered hospital for non-COVID reasons; Ronan Glynn (Deputy Chief Medical Officer and Head of the Department of Health's Health Protection Unit) took charge. 2 April A further 402 cases and 13 deaths were announced, bringing the totals to 3,849 cases and 98 deaths. Chief Medical Officer Tony Holohan said of the intensive care unit (ICU) figures: "Of 148 cases admitted to ICU, 25 of those cases have been discharged, sadly there have been 14 deaths from ICU and 109 remain in ICU. The median age of ICU admission is 62." 3 April A further 424 cases and 22 deaths were reported, bringing the totals to 4,273 cases and 120 deaths. One patient was discharged from Sligo University Hospital after being admitted to hospital for 10 days. 10 April A further 480 cases and 25 deaths were initially reported by the Department of Health, bringing the totals to 7,054 cases and 288 deaths. It was reported that there was a discrepancy between the number of cases confirmed by Ireland's Department of Health and the ECDC, due to swab tests sent to Germany for analysis to clear the backlog and testing in Ireland. 14,000 samples returned from German labs, of which 1,035 tested positive, bringing the total number of confirmed cases to 8,089. 62 patients admitted to ICU were discharged as of that date. Taoiseach Leo Varadkar announced that measures introduced on 27 March would be extended until at least 5 May. 11 April A further 553 cases, together with an additional 286 cases from previous samples sent to Germany, and 33 deaths were reported, bringing the totals to 8,928 cases and 320 deaths. Minister for Health Simon Harris said between 25,000 and 30,000 tests had been sent to Germany and "well over" half of the results had been returned, with the remainder due back by next week. 12 April A further 430 cases, together with an additional 297 cases from previous samples sent to Germany, and 14 deaths were reported, bringing the totals to 9,655 cases and 334 deaths. The National Public Health Emergency Team said there would be a "real danger" of a second wave of virus cases, if the changing of restrictions was not done correctly. 13 April A further 527 cases, together with an additional 465 cases from the backlog of tests at the laboratory in Germany, and 31 deaths were reported, bringing the totals to 10,647 cases and 365 deaths. Around 80% of cases are mild to moderate illness, close to 14% have severe disease and around 6% are critical. The Minister for Health claimed Ireland's approach to tackling COVID-19 was the "right strategy" that was "going to save lives". 15 April A further 657 cases, together with an additional 411 cases from the backlog of tests at the laboratory in Germany, and 38 deaths were reported, bringing the totals to 12,547 cases and 444 deaths. Among the deaths announced, a 23-year-old said to be the youngest person to have died in the country at the time. A spokesperson for the Ireland East Hospital Group confirmed the deaths of two healthcare workers, a man and a woman, at the same hospital in Kilkenny, the man having died at home the previous day and the woman having died in the hospital that day. 16 April A further 629 cases, together with an additional 95 cases from the backlog of tests at the laboratory in Germany, and 43 deaths were reported, bringing the totals to 13,271 cases and 486 deaths. One death, previously reported, was de-notified. The National Public Health Emergency Team reported that lockdown and other measures had driven the growth rate of the pandemic "as low as it needs to be" and was "close to zero". 18 April A further 630 cases, together with an additional 148 cases from the backlog of tests at the laboratory in Germany, and 41 deaths were reported, bringing the totals to 14,758 cases and 571 deaths. Chief Medical Officer, Tony Holohan, reported that the curve had flattened and that no peak would be coming. He said the lockdown should continue until 5 May and that the government should focus on contact tracing. 21 April – Chief Medical Officer Tony Holohan announced that 8,377 people had recovered in the community and that 856 people were discharged from hospital as of that date. It was also announced that one previously reported death was no longer classified as related to COVID-19. 24 April – A further 577 cases and 37 deaths, and 185 probable deaths were reported, and 2 deaths previously reported were reclassified as unrelated to COVID-19, bringing the totals to 18,184 cases and 1,014 deaths. The HPSC defined a probable death as "a death where a lab test had not been done but where a doctor believed a death was associated with current COVID-19." The total number of deaths included probable deaths in accordance with advice from the ECDC. 28 April – A further 299 cases were initially reported but the number was corrected to 229 by Chief Medical Officer Tony Holohan, and 59 deaths were reported, bringing the totals to 19,877 cases and 1,159 deaths. 2 previously notified deaths were de-notified. 29 April – Chief Medical Officer Tony Holohan said "We estimate that as of Saturday 25th April 12,222 COVID-19 cases (64%) in the community have recovered. 1,164 cases (6%) have been discharged from hospital which gives us a total recovery rate of 70%." 30 April – A further 359 cases and 43 deaths were reported, bringing the totals to 20,612 cases and 1,232 deaths. 1 previously notified death was de-notified.

May 2020 1 May