Did you know that you can apply online for a Tax Clearance Certificate?
In my experience, this is the easiest and fastest way to receive a Tax Clearance Certificate.
If your tax affairs are up to date, you should normally expect to receive your Certificate by post, within a week or so. Otherwise you will receive a letter from Revenue listing any outstanding balances or returns. Once you resolve these, your Certificate can then be issued.
This online service does not apply to PAYE taxpayers, Irish non-residents, or Standards In Public Office (SIPO) applicants.
If you are in one of these categories, just complete the paper form and submit it to your local Revenue Office.