Sunday 17th March 2012 (St Patrick's Day) is a public holiday in Ireland.
Monday 18 March is a bank holiday, not a public holiday - but a large number of workplaces public transport providers and shops will operate as they usually do on Sunday.
Galway City Bus services
Bus Éireann will run according to the Sunday timetable on Sun 17th and Mon 18th. There will be slight diversions around Eyre Square area while the parade is on.
City Direct will run according to the Sunday timetable on Sun 17th and Mon 18th, but with one extra bus from Cappagh Rd to the city at 10:45am. Services will end at the Cathedral until the parade is over.
Running full NiteLink services on Fri 15th, Sat 16th and Sun 17th. Enhanced Sunday service (starting at 10am) on Sun 17th, to get people to the parade in Galway city. Regular Bank Holiday service on Mon 18th.
Are running a reduced service on both 17 and 18 March. Details.
Have not made specific announcements: it is likely that they will run regular Sunday services from Sun 17th - Mon 18th inclusive. See Regional Bus Services for a full listing of all companies involved.
Many towns will have parades around midday: bus services at this time could be delayed due to road closures.