According to the Irish government’s updated COVD-19 travel policy, “This [14-day] period of restricted movement can end if you receive a negative result of a PCR test that has been taken a minimum of five days after your arrival in Ireland. You should wait for your negative test result to be returned before ending the period of restricted movements.”
The quarantine could last longer than five days, of course, depending on how long it takes to receive your test result. If you’re arriving in Ireland from overseas, you’ll also be required to fill out a passenger locator form online to help with contact tracing.
It’s important to note that availability of testing can’t be guaranteed upon arrival, so it’s advisable to make an appointment for a test in advance. The test result must be provided by the test provider to the HSE public health department for verification, and only PCR tests are considered admissible. 