Several countries require visitors to show proof of a recent COVID test before they’ll allow you to enter. Generally speaking the airlines will check that you fulfil the requirements before they let you board, though if you’re getting a connecting flight in one of the major European hubs like Schipol, CDG or Frankfurt they’re probably not going to be checking for your final destination when you board in Dublin.
Generally speaking self-administered home kits are not acceptable, as there’s no way of knowing who actually took the test.
For some countries a supervised antigen test will be acceptable, while for others they may require a PCR test.
There are several private companies offering tests for travel, though most of them are in the Greater Dublin area, which isn’t very helpful if you’re down in Kerry!
The Irish government is maintaining a list of test providers which is organised by province and by county.
You can find the list here. Some of the providers are private companies, while others are pharmacies. A lot of them will only offer antigen tests and not PCRs, so check what you need, as you might need to select a different test provider. Based on experiences with various friends over the last while I’d recommend booking in advance where possible, as many of these places will have a limited number of slots available.
The requirements for entry into other countries is constantly changing, so I’d recommend checking the Department of Foreign Affairs site for the latest advice.
Many of the airlines and hotels are offering flexible cancellation policies at the moment, so if you need to change your plans due to the constantly shifting landscape of restrictions and rules then you should be okay. You might be able to rebook for a later date or get either a refund or a voucher. However you should always check your booking to confirm its conditions.