Almost 200,000 Irish passport applications were received from Britain and Northern Ireland this year.
The number from England, Scotland and Wales increased by more than a fifth compared to 2017, the Republic's Department of Foreign Affairs said.
Foreign minister Simon Coveney said the total had risen since the Brexit vote in June 2016.
Out of the total number of applications received this year by the Passport Service, 84,855 applications were from Northern Ireland and 98,544 applications were received from Great Britain.
These figures represent an increase of 2 per cent and 22 per cent, respectively, over 2017 figures.
Mr Coveney said 2018 was a record-breaking year.
A total of 822,581 travel documents were issued.
Mr Coveney said: "The success of the online passport renewal service was recognised during the year at the CX Impact Awards, where it won the Impact in Digital award, and was ranked as the top Irish public sector organisation in terms of customer experience for the third year in a row.
"It is important that the Passport Service continues to use technology in order to gain efficiencies and deliver the best possible service to the citizen.
"This expanded service is an example of that, and will permit all citizens, both adults and children, to renew their passports online 24/7 from anywhere in the world."
