| MD | Players | Nationality | DOB | A(D) |
|---|---|---|---|---|
| 10-Mar-2012 | Peter O'Mahony | Ireland | 17-Sep-1989 | 22(175) |
| 05-Feb-2012 | Conor Murray | Ireland | 20-Apr-1989 | 22(291) |
| 05-Feb-2012 | Cian Healy | Ireland | 07-Oct-1987 | 24(121) |
| 25-Feb-2012 | Keith Earls | Ireland | 02-Oct-1987 | 24(146) |
| 05-Feb-2012 | Sean O'Brien | Ireland | 14-Feb-1987 | 24(356) |
| 05-Feb-2012 | Fergus McFaddon | Ireland | 17-Jun-1986 | 25(233) |
| 05-Feb-2012 | Stephen Ferris | Ireland | 02-Aug-1985 | 26(187) |
| 05-Feb-2012 | Jonathan Sexton | Ireland | 11-Jul-1985 | 26(209) |
| 05-Feb-2012 | Andrew Trimble | Ireland | 20-Oct-1984 | 27(107) |
| 05-Feb-2012 | Tommy Bowe | Ireland | 22-Feb-1984 | 27(348) |
| 05-Feb-2012 | James Heaslip | Ireland | 15-Dec-1983 | 28(52) |
| 10-Mar-2012 | Donnacha Ryan | Ireland | 11-Dec-1983 | 28(90) |
| 05-Feb-2012 | Robert Kearney | Ireland | 26-Mar-1983 | 28(316) |
| 05-Feb-2012 | Rory Best | Ireland | 15-Aug-1982 | 29(174) |
| 10-Mar-2012 | Eion Redden | Ireland | 20-Nov-1980 | 31(110) |
| 05-Feb-2012 | Gordon D'Arcy | Ireland | 10-Feb-1980 | 31(360) |
| 05-Feb-2012 | Mike Ross | Ireland | 21-Dec-1979 | 32(46) |
| 05-Feb-2012 | Paul O'Connell | Ireland | 20-Oct-1979 | 32(108) |
| 05-Feb-2012 | Donncha O'Callaghan | Ireland | 24-Mar-1979 | 32(318) |
MD = Match date,
DOB = Date of birth,
A(D) = Age(days).