Entitlement to Irish citizenship is based on the Irish Nationality and Citizenship Acts 1956 to 2004. Under the legislation, the basic requirement for obtaining citizenship by descent, through Foreign Birth Registration (FBR) is that one of the applicant’s parents was an Irish citizen at the time of the applicant’s birth.
An application for Irish citizenship through FBR can be submitted by any person with a grandparent born in any part of Ireland or by any person whose parent received Irish citizenship or was deemed to be an Irish citizen prior to the birth of the applicant. The parent could have obtained Irish citizenship through Foreign Birth Registration, Naturalisation, Post-nuptial Citizenship or Adoption.
However, if a person had a great grandparent born in Ireland and their parent through whom they wish to obtain citizenship had not themselves registered as an Irish citizen, then that person is not entitled to apply.