Viacom beat Bus Media in the final stage, and brands such as Vodafone and NiQuitin have already signed up.
Dublin Airport was used by 17 million passengers in 2004, and a further 7m came to the airport to meet and greet travellers.
Aircoach serves the capital's key upscale retail areas and principal hotels, using some of the busiest traffic routes.
It offers access to motorists and pedestrians, Irish travellers and tourists from abroad.
Tom Goddard, chief executive of Viacom Outdoor Ireland, said: "This is a fantastic advertising environment for brands wishing to reach consumers on the move.
These are some of the highest profile and most-trafficked routes in the country."