An Post's mail business has declined in line with international trends, however, it has been offset by a 40% volume growth in parcels, as more and more people shop online.
If parcel volumes from the UK fall post-Brexit, it will affect business for An Post, but the company says it is Brexit ready.
Debbie Byrne, Managing Director of An Post Retail, said, "We have had active conversations with all of our large international and UK parcel operators. They are also prepared for this.
"A lot of those operators have warehouses in other parts of Europe and we have been engaging with them should their supply chain change," Ms Byrne said.
"We are very much prepared and working with suppliers and with Royal Mail to deal with shifts that will inevitably occur, because consumers will seek out value and switch their source of purchase, and we're ready for that," she added.
An Post delivered a strong financial performance in 2018 with revenue up 7% at €897m. Operating profit increased from €8m in 2017 to €40m in 2018.
The company has seen strong growth in its financial services business, particularly in foreign exchange and current accounts, but there was a decline in business in terms of social welfare.
"Our profit growth is driven through tight cost control, and that's our labour and other costs," Ms Byrne said.
An Post has gone through a period of consolidation with the closure of 152 post offices across the country, mostly in rural areas.
The closures have met resistance from local communities, but An Post said it was necessary to ensure the business remains sustainable.
"With 950 post offices nationally, we really are the largest retail network across the country," Ms Byrne said.
"The closures of those post offices really ensured that the business transferred to neighbouring post offices, ensuring that they are sustainable. We want to maintain a strong network of post offices across the country and to do that, some consolidation was necessary," she added.