It is not mandatory to take a pre-departure COVID-19 test before travelling to Ireland however you will have to complete an online Passenger Locator Form (Opens in new windowsee here). Ireland adopted the EU Traffic Light system on the 8th November 2020, and all passengers arriving from a red, orange or grey region will be required to restrict their movements for 14 days upon arrival in Ireland.
Restrictions do not apply to passengers from green regions. Please see the official EU website Opens in new windowhere.
The period of 14 days to restrict movements can be waived for passengers arriving from an orange region if they have received a negative COVID-19 PCR test result during the three days before arriving in Ireland. In this case, passengers are requested to have supporting evidence of the negative test in their possession, according to Irish Government guidelines.
Arriving passengers from red regions do not have to continue to restrict their movements for the full 14 days, if they have a negative/not-detected result from a PCR test taken at least five days - i.e. a minimum of five days - after arrival in the State. The Irish Government advises that in this case, you should wait for your negative test result to be returned before ending your period of restricted movements.
It is the responsibility of the passenger to ensure that any test certificate issued from a COVID-19 testing facility sufficiently meets the local entry requirements of the destination country, state or region including any connecting airport requirements. Certain locations may require the test result to be translated into the local language at each location. Passengers should check local requirements and keep up to date as they evolve.