Train and bus fares are to rise by an average 3%, with the company responsible for the services blaming rising costs.
Translink said many of its fares would remain unchanged when the rise was introduced on April 30, including a freeze on the existing ticket cost for the Belfast to Dublin Enterprise rail route.
But the organisation said that having kept fares low despite increased fuel costs over the last two years, changes now had to be made to the cost of a number of Metro, railway and Ulsterbus services.
Translink marketing executive Ciaran Rogan said: "Fares on average are rising by 3%. This is unfortunately necessary as many of our costs are rising sharply - but we have kept it as low as possible and below inflation."
He said: "We have held all our fares for almost two years despite the rising fuel costs and we know our customers really appreciated this fares freeze in these tough economic times.
"More and more people are already using our great everyday value tickets and offers for bus and train travel particularly as fuel and motoring costs have continued to rise.
"We have been working very hard to reduce our costs and keep any fare rises as low as possible.
"We have managed to keep many fares unchanged, once again we have held our smartlink multi journey fares for Metro bus journeys so many of our customers should not have to pay any more if they simply move onto these great value cards.
"They can be loaded with as few as five journeys to be used over 12 months and the majority of Metro passengers can save as much as 40% compared to paying cash."
Mr Rogan added: "We strongly urge passengers to look for the best deal by visiting our website www.translink.co.uk, calling our contact centre 028 90 66 66 30, or visiting their local bus or train station to see how to get the lowest fare using smartlink products, weekly, monthly or annual tickets or any of our regular special fare deals and start saving."