Road restrictions are in place in cities and towns across the country today to facilitate hundreds of St Patrick's Day parades.
More than 120 events are taking place nationwide, with one of the most unusual in Carrick-on-Shannon in Co Leitrim.
The River Shannon boating parade, which begins immediately after the land parade, will have cruisers, fishing boats, ribs, speed boats and jet skies. St Patrick himself will appear as a figurehead on one of the vessels.
Meanwhile, the town's answer to David Blaine - local businessman Gerry McCormack - is trying to raise money for Haiti by suspending himself 180 feet above the River Shannon, in a glass box, for 48 hours.
The biggest parade in Dublin City Centre expected to begin at 12 noon.
Soccer Legend John Giles is this year's Grand Marshall and will lead the parade as it makes its way from Parnell Square to St Patrick's Cathedral.
In Galway city, some 60,000 spectators are expected to line the streets for the annual parade, which runs from 11.30am to 1.30pm, starting on Fr Griffin Road and taking in Dominic Street, Bridge Street, Shop Street and finishing on Eyre Square.
The Cork City parade begins at 1pm on South Mall, with some 3,000 performers taking part.