In May 2009, D'Arcy was named in the Barbarians squad to play England and Australia along with Ireland teammate Geordan Murphy and Leinster colleague Rocky Elsom., the Barbarians ended up beating England by 33 points to 26, with D'Arcy scoring one of the tries. On 3 June 2009, D'Arcy was called up for the British & Irish Lions squad for the tour in South Africa due to injuries in the squad. He featured for Ireland against Fiji and South Africa during the 2009 November Tests, and started every game in the 2010 Six Nations. He started against New Zealand in the 2010 Summer Tests and scored 1 try, but a groin problem kept him out of Ireland's remaining test against Australia. He earned his 50th cap against South Africa on 6 November 2010.