 In the second round match against Colombia under-20, he came on as a late substitute to assist Kevin Doyle's goal and help turn the game around, coming back from a two-goal deficit only to lose on the golden goal.On 25 May 2010, Fahey won his first senior cap for the Republic of Ireland in a 2–1 win against Paraguay at the RDS Arena, replacing Damien Duff in the 77th minute.He made his first start against Argentina on 12 August, in the first international match at the new Aviva Stadium.