If you want to go shopping in Ireland or visit an attraction you can do so at nearly any civilized time - but it helps to know the basic rules when to venture out. Obviously, there are a number of special exceptions in Ireland (public holidays in the Republic of Ireland are not always identical to public holidays in Northern Ireland), but you can discern some basic rules. They might vary locally, though.
Here are some general hints on when you should find doors not firmly locked:
High Street Shops
Most High Street Shops (shops in the central urban areas) will usually open between 9 and 10 am and close between 5 and 6 pm, Monday to Saturday. Lunch breaks are rare but some county towns may have early closing days. Some large county towns and the cities have Sunday opening between noon and around 6 pm. The same rule applies for opening on public holidays.
Malls and Shopping Centres
Most malls and shopping centres open around 9 am and close at different times - expect 6 pm from Monday to Wednesday and on Saturday, 8 pm on Thursday and Friday. Sunday and public holidays opening times would be between noon and 6 pm. These would be the general opening times for the whole mall, individual shops may open later and close earlier.
Generally open along the same lines as High Street Shops, but with some supermarkets staying open until midnight and a few even open 24 hours (often excluding Sundays).
These small shops usually cater for the commuter and working professionals - which means they open around 7 am and close around 9 to 10 pm from Monday to Saturday, noon to 6 pm on Sundays.
You will find some gas stations with 24/7 service in the larger urban areas and along major routes, otherwise opening hours similar to convenience stores apply. Bear in mind that motorway service stations are still few and far between.
Banks are generally open from 10 am to 4 pm Monday to Friday and will definitely be closed on public holidays. There may be an extended lunch break in-between.
Most post offices are open 9 am to 5 or 6 pm from Monday to Friday, occasionally with a lunch hour around 1 pm in rural areas. Larger post offices are open on Saturday (mornings in most cases), but all will usually be closed on public holidays.
Expect most museums to be open between 10 am (noon on Sundays) and 5 or 6 pm. Some museums are closed on Mondays and some on public holidays (especially the National Museums in Dublin).
Expect most attractions to be open between 10 am (noon on Sundays) and 5 or 6 pm. Some attractions are closed outside the season (late March to October) or operate limited opening hours, especially those in rural areas. Check before travelling ...
Pubs should be open between noon and midnight as a rule of thumb - expect some pubs to be closed on Sundays, especially in Northern Ireland.
Public Transport during the week generally kicks in at 6 am for commuters, at 7 am in the urban areas and then starts to wind down from 7 pm. Only few selected services are running after 11 pm. Saturday services start later and Sunday services are severely less frequent. On public holidays Sunday timetables apply.
As always it is advised to check opening times before travelling longer distances to avoid disappointment!