Roots Revealed can undertake research for the required Birth and Marriage records to prove Irish ancestry for an individual who wants to apply for Irish citizenship and an Irish passport. You must be registered as an Irish citizen before you can apply for an Irish passport.
Being an Irish citizen means that you are formally recognised as a national of Ireland and a citizen of the European Union. It gives you certain rights, including the right to carry an Irish passport, live and work in Ireland and the EU, and receive consular help from Irish embassies and consulates abroad.
Claiming citizenship through descent from an Irish parent or grandparent applies to those born anywhere on the island of Ireland, including Northern Ireland. The situation if you are claiming citizenship through descent from an Irish great-grandparent is a little more complex and further information may be found at the Irish Naturalisation and Immigration Service.
The Irish Naturalisation and Immigration Service has a handy guide to walk you through whether you may be entitled to Irish citizenship.
The Department of Foreign Affairs and Trade processes applications for citizenship through Foreign Births Registration and more information may be found on their website.