Children can travel free on all public transport services covered by the Leap Card for two weeks from today.
Free travel will automatically apply to any holder of a Child Leap Card when the card is presented.
The promotion covers the vast majority of public transport journeys.
This includes Dublin Bus (excluding Airlink), Luas, DART, commuter rail services in the "Short Hop Zone" and Bus Éireann services where Leap Card Validators are available.
Anne Graham, CEO of the National Transport Authority said: "Of course, this promotion doesn't just apply to Dublin. The historic cities of Cork, Galway, Limerick and Waterford are also included.
"At a time when a lot of people still find themselves under financial pressure, we want to do everything we can to make it easier for families to get out and enjoy all there is on offer throughout the network of public transport services covered by Leap."
This offer is valid for Child Leap Card 4-15 and Child Leap Card 16-18, which is valid up to the holder's 19th birthday, as long as the card has at least 1 cent credit.