Carat will replace Mindshare on the business after a final head-to-head pitch between them.
The agency will be responsible for handling Tourism Ireland's media arrange-ments in the UK, the US, France, Germany, Spain, Italy, Sweden, the Netherlands, Canada and Australia.
Tourism Ireland has informed pitching agencies that Carat has won the business but, as part of the statutory process, they are subject to a government-imposed "standstill" period, in which unsuccessful agencies may seek clarification of the process.
Brian Twomey, the head of marketing at Tourism Ireland, said: "We are unable to confirm the appointment until 27 May, following a contract being signed."
Carat's appointment follows that of Publicis UK to Tourism Ireland's global creative account this month. The agency won a pitch against Bartle Bogle Hegarty, Saatchi & Saatchi and the incumbent, JWT London.
Carat and Publicis will begin working with the tourist board in 2012, and will initially hold a four-year contract, with the option to extend annually for a further three years.
Tourism Ireland kicked off a review of its global advertising business in October last year. Agency Insight handled the review.