The increased cost will come into effect from February 27th.
The cost of a stamp is rising again.
From the 27th of February the cost of posting a letter will jump by 25c to €1.65.
An Post says its needed because operating costs are rising while the number of letters posted has fallen by 8% in the past year.
Aontú party leader and Meath West TD Peadar Tobin says it will hit businesses and older people the hardest: