Earls made his debut for Ireland in November 2008 against Canada in Thomond Park. He scored his first international try with his first touch of the ball. Earls was selected in Ireland's squad for the 2009 November Tests. He came on for the injured Luke Fitzgerald against Australia and started against Fiji, a game in which he scored two tries, and South Africa. He played in all 5 of Ireland's 2010 Six Nations Championship games, starting 4 of them. He scored a try against England and scored two more against Wales, finishing as joint top try scorer with Tommy Bowe, Shane Williams and James Hook.