Will an Irish visa allow me to travel to Northern Ireland?
A - No. – If you wish to travel to Northern Ireland you will require a UK Visa.
If you are travelling to the Republic of Ireland, and you intend to also visit Northern Ireland and return to the Republic, you must obtain a multiple-entry Irish visa and a UK visa.
If your main destination is Northern Ireland but you arrive in, and depart from the Republic of Ireland, you must first obtain a UK visa, and then a multi-entry Irish visa.
Northern Ireland consists of Counties Antrim, Armagh, Derry, Down, Fermanagh and Tyrone.