Always check the details on your visa as soon as you receive it, to ensure there are no problems before you travel.
Your visa includes four main pieces of information. They will dictate how often you can travel to Ireland and how long you can stay when permitted entry.
How often can I travel?
This depends on two things: the number of entries and the validity dates.
Number of entries
If, under number of entries, your visa states 01 then you can only travel on it once. Otherwise, if it says Multi you can travel as many times as you like, until you have exceeded your duration of stay.
Validity dates (From... Until)
Your visa is valid for travel on any day starting from the date listed From and ending on the date listed Until. These dates are the visa validity dates. Always beware of time zone changes if you are travelling on the visa expiry date.
How long can I stay?
This depends on two things: the type of visa and the duration of stay.
Type of visa
Non-EU/EEA/Swiss/UK nationals, including those with an Irish visa, can only stay for up to 90 days on each visit.
If you need a visa to enter Ireland, and you wish to live in Ireland, you must have a D-type visa (long-stay). If you need a visa to enter Ireland, and you only wish to visit, then you will have a C-type visa (short-stay)
Duration of stay
If, on your visa, there is a specific duration of stay (e.g. 14) then on each entry, you can only stay for this number of days. If the duration of stay is XX, then you can stay for up to 90 days. Irish border control may permit you less than 90.
D-type visa holders must register as a resident within 90 days of entering Ireland. Persons who register for residence receive an Irish Residence Permit (IRP). The IRP allows you to live in Ireland and travel in and out until it expires. If you do not register you must leave after the 90 days has passed from date of entry. For more information see: https://www.irishimmigration.ie/registering-your-immigration-permission/
The longest a C-type visa holder can stay in Ireland is 90 days on each visit. This can be shorter depending on the entry stamp you receive from Irish border control. Always check your entry stamps, and leave by they day stamped into your passport. Failing to leave Ireland on time is a serious breach of immigration controls.
A C-type visa holder cannot remain in Ireland for more than 90 days in any 180 day period or more than 180 days in any 365 day period. These periods begin on the date of first entry.
You hold a C-class multi entry visitor visa, valid from 1 January 2023 until 31 December 2023.
You enter on 1 January and border control permits you to stay the full 90 days, requiring you to leave on 1 April. You leave on 1 April. On 1 May you want to return to Ireland.
In this case, as you have exhausted your 90 days, you must wait until the 180 days have passed, since date of first entry, before you can return. So, the earliest you can travel back to Ireland is on 30 June, where you will again get stay of up to 90 days.
You enter on 1 January and border control permits you to stay the full 90 days, requiring you to leave on 1 April. You leave on 28 February. On 1 May you want to return to Ireland.
While you could have stayed for 90 days, you in fact only stayed for 59. This means you have 31 days left out of the 90. This means that you can return on 1 May, but you must leave by 1 June.