Introduction

The Irish number plate scheme was devised in 1904. Similar to the British formula, it includes letters and numbers. The older schemes (and the one still in use in Northern Ireland) always contained the letters I or Z, to differentiate them from British registrations, which cannot contain either of those letters.

Three schemes have been in use up to the time of writing; the original 1904 version, one introduced around the 1920s, and then an all new scheme for the Republic in 1987.

Northern Irish numbers are legal on UK vehicles, and because of this, many people named BAZ, CAZ and GAZ are very happy people, since the NI plates are generally much cheaper than other personalized registrations.

1904

The 1904 system was similar to the UK system of the time, with three letters, the second and third of which denoted where the vehicle was registered, this is not mnemonic, but applied alphabetically.

The following table shows the region code, and name of the region. An example would be SIB 3942, which has the region code of IB for Armagh.

Exhaustion

As numbers were exhausted, a second system, using the letter Z, instead of I, was applied. These were allocated at various times according to need:

  • Z, ZA, ZC, ZD, ZE, ZH, ZI, ZJ, ZL, ZO, ZU, ZV - Dublin
  • ZB, ZK, ZT - Cork (from 1935)
  • ZF - Cork City
  • ZM - Galway
  • ZN - Meath
  • ZP - Donegal
  • ZR - Wexford
  • ZW - Kildare
  • ZX - Kerry
  • ZY - Louth
  • ZZ - Temporary Imports
  • AZ, CZ, EZ, FZ, GZ, MZ, OZ, PZ, TZ, UZ, WZ - Belfast
  • BZ, JZ, SZ - Down
  • DZ, KZ, RZ - Antrim
  • HZ, VZ - Tyrone
  • LZ, XZ - Armagh
  • MZ, YZ - Londonderry

1987 Onwards

In the Republic of Ireland, a new formula was introduced in 1987. This includes the year of registration, the location of registration (in a much easier to understand mnemonic form), and a serial number.

As an example, 02-D-12345 was the 12,345th vehicle to be registered in Dublin in the year 2002. In a small county, such as Louth you may see numbers only reaching into the early thousands, whereas five digits are not uncommon in larger or more populous areas.

Since 1991 Irish plates have featured the blue euro tag (the european stars emblem, with IRL written below), and many feature the name of the registration area in Gaelic.

  • CW - Ceatharlach (Carlow)
  • CN - An Cabhán (Cavan)
  • CE - An Clár (Clare)
  • C - Corcaigh (Cork)
  • DL - Dún na nGall (Donegal)
  • D - Baile átha Cliath (Dublin)
  • G - Gailimh (Galway)
  • KY - Ciarraí (Kerry)
  • KE - Cill Dara (Kildare)
  • OY - Uíbh Fháilí (Offaly)
  • LM - Liatroim (Leitrim)
  • LK - Luimneach (Limerick)
  • LD - An Longfort (Longford)
  • LH - An Lú (Louth)
  • MO - Maigh Eo (Mayo)
  • MH - An Mhí (Meath)
  • MN - Muineachán (Monaghan)
  • LS - Laois (Laois)
  • RN - Ros Comáin (Roscommon)
  • SO - Sligeach (Sligo)
  • TN - Tiobraid Árann (Tipperary North)
  • TS - Tiobraid Árann (Tipperary South)
  • WD - Port Láirge (Waterford)
  • WH - An Iarmhí (Westmeath)
  • WX - Loch Garman(sic) (Wexford)
  • WW - Cill Mhantáin (Wicklow)
  • L - Luimneach (Limerick City)
  • W - Port Láirge (Waterford City)

Source:
http://www.asharte.freeserve.co.uk/veh_tab.htm