Vehicle registration plates of the Republic of Ireland Vehicle registration plates of the Republic of Ireland In the Republic of Ireland, vehicle registration plates (commonly known as "number plates") are the visual indications of motor vehicle registration – officially termed "index marks" – which it has been mandatory since 1903 to display on most motor vehicles used on public roads in Ireland. The alphanumeric marks (or "registration numbers") themselves were issued by the local authority in which a vehicle is first registered. The current specification for number plates is the format YYY–CC–SSSSSS. Those issued from 1987 to 2012 had the format YY–CC–SSSSSS. The components are: Since 1991, the
International vehicle registration code system is used for vehicles belonging to the diplomats of foreign countries with license plate from the host country. That system is host country-specific and varies largely from country to country. For example TR on a diplomatic car in the USA indicates Italian, not Turkish. Such markings in Norway are indicated with numbers only, again different from international standards (e.g. 90 means Slovakian. International vehicle registration code The country in which a motor vehicle's vehicle registration plate was issued may be indicated by an international licence plate country code, formerly known as an International Registration Letter or International Circulation Mark.