More than a quarter of a billion journeys were made on public transport last year.
Bus Éireann, Dublin Bus, Irish Rail and the Luas carried 251 million passengers between them in 2017 - an increase of 16 million on the previous year.
The National Transport Authority say the numbers could grow further this year thanks to the extended Luas Green Line, and a new Kilkenny city bus service.
CEO Anne Graham says the economy is improving.
She said: "There is more people in employment, more people shopping and going into town for retail and leisure purposes.
"We are delighted that more people are using public transport to access those facilities."
- Digital Desk