| MD | Players | Nationality | DOB | A(D) |
|---|---|---|---|---|
| 20-Mar-2021 | Jonathan Sexton | Ireland | 11-Jul-1985 | 35(253) |
| 20-Mar-2021 | Keith Earls | Ireland | 02-Oct-1987 | 33(170) |
| 14-Mar-2021 | Cian Healy | Ireland | 07-Oct-1987 | 33(159) |
| 20-Mar-2021 | Dave Kilcoyne | Ireland | 14-Dec-1988 | 32(96) |
| 20-Mar-2021 | Conor Murray | Ireland | 20-Apr-1989 | 31(334) |
| 07-Feb-2021 | Peter O'Mahony | Ireland | 17-Sep-1989 | 31(144) |
| 20-Mar-2021 | CJ Stander | Ireland | 05-Apr-1990 | 30(350) |
| 20-Mar-2021 | Bundee Aki | Ireland | 07-Apr-1990 | 30(348) |
| 20-Mar-2021 | Robert Herring | Ireland | 27-Apr-1990 | 30(328) |
| 14-Feb-2021 | Rhys Ruddock | Ireland | 13-Oct-1990 | 30(125) |
| 20-Mar-2021 | Iain Henderson | Ireland | 21-Feb-1992 | 29(28) |
| 14-Mar-2021 | Jamieson Gibson-Park | Ireland | 10-May-1992 | 28(308) |
| 14-Mar-2021 | James Lowe | Wales | 08-Jul-1992 | 28(249) |
| 20-Mar-2021 | Jack Conan | Ireland | 29-Jul-1992 | 28(234) |
| 20-Mar-2021 | Tadhg Beirne | Ireland | 01-Aug-1992 | 28(231) |
| 20-Mar-2021 | Tadhg Furlong | Ireland | 14-Nov-1992 | 28(126) |
| 20-Mar-2021 | Josh van der Flier | Ireland | 25-Apr-1993 | 27(329) |
| 20-Mar-2021 | Robbie Henshaw | Ireland | 12-Jun-1993 | 27(281) |
| 14-Feb-2021 | Billy Burns | Ireland | 13-Jun-1994 | 26(247) |
| 14-Mar-2021 | Gary Ringrose | Ireland | 26-Jan-1995 | 26(48) |
| 14-Feb-2021 | Andrew Porter | Ireland | 16-Jan-1996 | 25(30) |
| 20-Mar-2021 | Jacob Stockdale | Ireland | 03-Apr-1996 | 24(351) |
| 14-Mar-2021 | Will Connors | Ireland | 04-Apr-1996 | 24(344) |
| 20-Mar-2021 | Hugo Keenan | Ireland | 18-Jun-1996 | 24(275) |
| 14-Mar-2021 | James Ryan | Ireland | 24-Jul-1996 | 24(233) |
| 27-Feb-2021 | Jordan Larmour | Ireland | 10-Jun-1997 | 23(262) |
| 27-Feb-2021 | Ronan Kelleher | Ireland | 24-Jan-1998 | 23(34) |
MD = Match date,
DOB = Date of birth,
A(D) = Age(days).