Translink has announced a 3% rise in the cost of Metro tickets and 5% for journeys on NI Railways, which will come into effect next month.
The company argued it's the first increase on some fares in several years and encouraged customers to use smart passes and multi-journey ticket deals to save money.
Ciaran Rogan said: "We have worked very hard to keep fare increases as low as possible, and indeed, over recent years, our fares have not kept up with inflation.
"Notably, this will be the first increase on some fares for five and even six years.
"Customer satisfaction remains high as customers appreciate the many improvements we have made to our fleet, technology, ticketing together with innovative promotions. We look forward to seeing more people try the bus and train over the coming weeks and months".
However the Committee for Regional Development has criticised the price hike.
Chairman Jimmy Spratt, of the DUP, said: "The department has tried to sugar-coat these increases by saying that rail fares will be held until 2015 and that these increases are less than any in the UK and Ireland.
"That will be of little consolation to those hard-pressed customers who have shown faith in Translink over the years, particularly in the very difficult economic situation in which we find ourselves."
The new prices come into effect from 6 May.