Tens of thousands of commuters are preparing to brave traffic-choked roads, packed trains and airline strikes as the bank holiday weekend gets under way.
Severe traffic congestion and long delays are expected on all major routes throughout the weekend, particularly on the Dublin road to Cork as music lovers flock to the Guinness Jazz Festival.
Iarnród Éireann is advising passengers travelling to the city to book seats in advance as all regular services from Dublin to Cork are subject to a reservation system.
Bus Éireann, which expects to carry 100,000 passengers this weekend, is also running a fleet of special coaches from Dublin to Cork today at 2 p.m.
It is asking all customers on intercity routes to travel on morning and afternoon services, where possible, to avoid the expected heavy traffic.
Met Éireann, meanwhile, is forecasting a mostly cold weekend, with sunny spells and blustery scattered showers. Milder weather is expected on Monday, with dry weather and some sunny spells forecast for most areas.
In Dublin no DART services will operate south of Pearse Station on Saturday or Sunday as part of continuing work to upgrade the railway system.
Dublin Bus, however, says it is doubling the number of buses operating on routes adjacent to the DART on the southside to help meet the extra demand.
There will also be disruption for passengers travelling to Belfast by train from Dublin, with bus transfers taking passengers between Drogheda and Dundalk due to renewal works.
Getting around Dublin by car may also prove difficult on Monday, with major routes closed to accommodate the Dublin City Marathon.
If the roads are likely to be bad, the airports could be even worse as Aer Lingus prepares for another one-day strike on Monday, when 1,000 cabin crew go on strike.
Despite assurances that there would be little disruption during yesterday's one-day strike, many customers in Dublin Airport grumbled of delayed or cancelled flights.
Aer Lingus, however, insisted that any disruption was due mostly to poor weather conditions.
The ferries are also preparing for a busy weekend, with Irish Ferries and Stena Line expecting to carry around 95,000 passengers between them.