Good Friday (the 14th) is a bank holiday but not a public holiday in the Republic of Ireland: All banks and many public services (eg post-office) are closed, and some other companies treat the day like a public holiday and close anyway. However most public-transport run normal services, with a few exceptions.
Following a recent law change this is the first year when all pubs, hotel bars and off-licenses are allowed to be open on Good Friday if they usually open on Fridays. Anecdotal feedback is that most, but not all, will open,
Easter Saturday and Easter Sunday are not public holidays: usual Sat / Sun timetables generally apply.
Easter Monday is a public holiday and a bank holiday, and in most cases Sunday services will be run.
Information from specific bus and train companies is summarised below. Always confirm details with the company. Bookings are recommended, because there are a number of events happening this weekend.