The National Transport Authority has confirmed that increases are to be applied to fares on Dublin Bus, Iarnród Éireann, Bus Éireann and Luas.
These fare increases will take effect from December 1.
The authority admitted that some of the increases are "significant", and they are encouraging customers to use the Leap Card which, they say, will be substantially cheaper than the new fares.
In a statement they said: "The fares increases have been allowed in order to protect public transport service delivery as much as possible at a period when state subvention for public transport has been reduced each year since 2009, as a result of Ireland’s difficult economic circumstances.
"Compounding the problem have been falling patronage and farebox revenues and increasing fuel costs. Therefore, despite the companies’ cost-cutting programmes, fares increases are needed so that the transport companies can continue to run their services."
The authority also said that the Leap Card will be phased in for Bus Éireann customers from early 2013, and 2012 fares will apply on Leap.
The fare increases are:
Dublin Bus cash fares will rise by between 5.7% (for 13+ stages) and 17.9% (for 1-3 stages), with Leap increasing by 2.1% and 12% for the same journeys.
Prepaid tickets will also go up by 2.74% (Rambler 5-day child ticket) to 16.8% (Travel-90 10-journey ticket).
On Bus Éireann, fares have been increased by an average of 6% across all ticket types.
On Irish Rail, Dublin commuter fares will rise by 9.1% (Zone G adult single) to 14% (Zone A adult return).
Inter-city fares will increase by 0.89% to 3.92%.
Some Luas cash fares will remain unchanged, while others will go up by 5.7%.