Short-haul numbers were up 3.4pc but the strongest growth was in long-haul, particularly on US routes.
The number of people travelling on long-haul flights was up 13.7pc.
As part of The Gathering, some 8,000 people from around the world were invited to take part in the People's Parade on St Patrick's Day, which would have contributed to the rise in tourism numbers.
A big influx of visitors is also expected in the coming months as new routes from America open up.
Tourism Ireland chief Niall Gibbons said 2013 is looking like it will be a record year for visitors from North America.
"Last year was the second best year ever for tourism from North America," he said.
"There are new routes that have yet to be started. A new route from Philadelphia into Shannon with US Airways will begin in May. United Airlines from Chicago to Shannon will begin in June.
"Another route with American Airlines from JFK to Dubiln will begin in May also," he said.
He said both Delta and Aer Lingus have announced additional frequency or capacity on their existing Boston, Chicago and Orlando routes.
"There is no question that The Gathering has played a role. I have no doubt that the reason that some of these routes came about was because of The Gathering and the increased demand. It is great to see such capacity," he said.