The price of a standard international stamp is to increase to €1.50, An Post has confirmed.
It marks a 15c jump from the existing €1.35 rate, with the change effective from April 4th.
However, An Post says the standard Irish stamp rate will remain at €1 - the rate which was introduced last year.
Standard parcel rates also remain largely unchanged, although the price of sending a parcel weighing between 500g and 1kg will increase from €8 to €9.
Explaining this year's rates, An Post says mail reductions from the stamp price increase last year were 'less than anticipated', while the company's workforce has also decreased by 300 people.
In terms of the international letters, An Post says it "faces continuous unit cost inflation from reduced volumes".
In a statement, An Post CEO David McRedmond explained: “2017 saw a major improvement in An Post’s difficult financial position resulting from the price increase last April, large headcount reductions and the successful re-launch of the parcel business. An Post’s strategy is working well but the pressure needs to be maintained as the business offsets the impacts of e-substitution on mail volumes while refocusing the business on e-commerce.
"I am pleased that the better financial position means prices for standard letters and parcels need not be increased this year. The business has to work even harder in 2018 to deliver efficiencies, to continue implementing fair pricing and to launch new services.”
2017 saw a number of measures taken to address An Post's financial situation, including the Government providing a €30 million loan in a bid to help save rural post offices.
An Post posted a loss of €15.6m in 2016, but last year indicated it was on course to break even.
The company has made a number of other changes, including evening & Saturday parcel deliveries.