 Stringer was part of the Ireland teams that won the Six Nations Triple Crown in 2004, 2006, and 2007

On 14 March 2009, Stringer put in a Man-of-the-Match performance for Ireland against Scotland during the 2009 Six Nations Championship.Losing 12–9 at half-time in Murrayfield, Stringer made a break and passed to Jamie Heaslip, who scored a match-turning try that eventually saw Ireland win 15–22.A week later, Stringer came off the bench during Ireland's final 2009 Six Nations game against Wales.