You can't.
Ireland doesn't have postcodes or zip codes.
Addresses in Ireland take the form of
Ms Forename Surname
HouseNo Streetname
Villagename
Countyname
Ireland.
Addresses in much of Co. Dublin - the urban area around the capital city - have numerical postal zones allocated to easy sorting of post.
Although the postal prefix BT indicates Belfast, it covers the whole of Northern Ireland.
(See the Wikipedia link below)
Royal Mail website if you know the address of the location.
One can find London postal codes using various resources. One can find postal codes in London, England online at websites such as LondonTown and GeoNames.
get your postal code from here : http://find-postalcode.com/ and putting it in your account
The best place to find zip codes is the United States Postal Service (USPS) online website. You can also find postal zip codes at the website MyZipCodeMap.
The United States Postal Service official website is the easiest place to find the postal zip codes of cities. Websites such as Freemake and Phaster also allow you to find the postal zip codes of cities.
You can find the US postal zip code for Seattle by going to a postal zip code finder online. Another way to find US postal codes is to go to a post office. There are directories at post offices which list postal codes.
google search
On the island of Ireland you will find the country officially known as Ireland or Éire, sometimes referred to as the Republic of Ireland or incorrectly referred to as Southern Ireland. You will also find Northern Ireland on the island of Ireland.
The initials of the country where you will find Belfast are N.I. for Northern Ireland, which is part of the United Kingdom.
You can find postal zip codes by city at USPS.com. This site allows you to look up zip codes by street address, city and state. Or you can also look up zip codes within the city as well.
The postal code for the country of Pakistan is "PAKISTAN"
The giant's causeway in Northern Ireland.