The airport saw 10m people during the summer months.
A controversial passenger cap at Dublin Airport will be exceeded this year.
The warning from DAA comes after a record breaking summer, with 10m people through the doors at the airport.
The airport's operator says that means it won't comply with the annual 32m passenger limit.
Ryanair CEO, Mullingar's Michael O'Leary says the restriction is forcing airlines to divert planes away from Dublin - and should be scrapped: