Over 822,000 passports were issued in 2018, according to new figures from the Passport Service.
There were more than 6,500 applying in a single day during peak periods.
There's been a 22 per cent increase in the number of applications from Great Britain - with 98,544 applications processed for Irish residents in the UK this year alone.
Officials are expecting another record-breaking year in 2019, and an extra 300 staff are being employed for the Passport Service's offices in Dublin and Cork.
Tánaiste and Minister for Foreign Affairs, Simon Coveney, says Brexit is playing a key role in the rise in British applications.
He suggested: "As the Brexit process plays out, as more and more people want to hold on to the benefits of being an EU citizen as well as an Irish citizen, and if they're living in the UK... I think a lot of people who are eligible for an Irish passport are now thinking about accessing that passport, in a way that they wouldn't have three or four years ago."
According to the Passport Service, more than 7,000 passports were reported lost or stolen during the year.
Anyone who needs to renew their passport next year, meanwhile, is being encouraged to do so during the off-peak passport to ensure the shortest possible renewal time.