More than 27 million people passed through Dublin Airport between the beginning of the year and Sunday, breaking the 2015 record of 25 million.
Dublin Airport confirmed that it reached the milestone as the Christmas rush began in earnest a week ahead of the day itself.
The airport will close on Christmas Day, leaving 11 business days before the end of 2016.
Managing director Vincent Harrison described the new record as a major milestone. "We've seen growth from the vast majority of our major airline customers during the year and also across almost all major market sectors," he said.
He noted that airlines added 19 new routes this year and increased seats on 31 existing services.
Mr Harrison added that a strong November, normally a quiet month in aviation, helped push Dublin past its previous record.
Numbers during the month rose 9 per cent to two million, the first time that the airport has handled that many passengers during November.
Almost 83,000 people are expected to pass through Dublin Airport on Friday December 23rd, making it the busiest day of the Christmas period.