| MD | Players | Club | Nationality | DOB | A(D) |
|---|---|---|---|---|---|
| 20-May-2017 |  Keelan Giles | Ospreys | Wales | 29-Jan-1998 | 19(111) |
| 20-May-2017 | Sam Underhill | Ospreys | England | 22-Jul-1996 | 20(302) |
| 19-May-2017 |  Joey Carbery | Leinster | Ireland | 01-Nov-1995 | 21(200) |
| 19-May-2017 | Gary Ringrose | Leinster | Ireland | 26-Jan-1995 | 22(114) |
| 19-May-2017 |  Ryan Elias | Scarlets | Wales | 07-Jan-1995 | 22(133) |
| 19-May-2017 | Steffan Evans | Scarlets | Wales | 01-Sep-1994 | 22(261) |
| 19-May-2017 | Ross Moloney | Leinster | Ireland | 11-May-1994 | 23(8) |
| 19-May-2017 | Adam Byrne | Leinster | Ireland | 10-Apr-1994 | 23(39) |
| 20-May-2017 | Nicky Smith | Ospreys | Wales | 07-Apr-1994 | 23(43) |
| 20-May-2017 |  Rory Scannell | Munster | Ireland | 22-Dec-1993 | 23(149) |
| 19-May-2017 | Robbie Henshaw | Leinster | Ireland | 12-Jun-1993 | 23(341) |
| 19-May-2017 | Rhys Patchell | Scarlets | Wales | 17-May-1993 | 24(2) |
| 19-May-2017 | Josh van der Flier | Leinster | Ireland | 25-Apr-1993 | 24(24) |
| 19-May-2017 | Luke McGrath | Leinster | Ireland | 03-Feb-1993 | 24(105) |
| 19-May-2017 | Samson Lee | Scarlets | Wales | 30-Nov-1992 | 24(170) |
| 19-May-2017 | Tadhg Furlong | Leinster | Ireland | 14-Nov-1992 | 24(186) |
| 19-May-2017 | Tadhg Beirne | Scarlets | Ireland | 01-Aug-1992 | 24(291) |
| 19-May-2017 | Jack Conan | Leinster | Ireland | 29-Jul-1992 | 24(294) |
| 20-May-2017 | Tom Habberfield | Ospreys | Wales | 19-May-1992 | 25(1) |
| 19-May-2017 | Rob Evans | Scarlets | Wales | 14-Apr-1992 | 25(35) |
| 20-May-2017 | Niall Scannell | Munster | Ireland | 08-Apr-1992 | 25(42) |
| 20-May-2017 | Rhodri Jones | Ospreys | Wales | 23-Dec-1991 | 25(149) |
| 20-May-2017 | Andrew Conway | Munster | Ireland | 11-Jul-1991 | 25(314) |
| 19-May-2017 | Liam Williams | Scarlets | Wales | 09-Apr-1991 | 26(41) |
| 19-May-2017 | James Tracy | Leinster | Ireland | 02-Apr-1991 | 26(48) |
| 20-May-2017 | Francis Saili | Munster | New Zealand | 16-Feb-1991 | 26(94) |
| 19-May-2017 | James Davies | Scarlets | Wales | 25-Oct-1990 | 26(207) |
| 19-May-2017 | Rhys Ruddock | Leinster | Ireland | 13-Oct-1990 | 26(219) |
| 19-May-2017 | Scott Williams | Scarlets | Wales | 10-Oct-1990 | 26(222) |
| 19-May-2017 | Johnny McNicholl | Scarlets | Wales | 24-Sep-1990 | 26(238) |
| 19-May-2017 | Gareth Davies | Scarlets | Wales | 18-Aug-1990 | 26(275) |
| 20-May-2017 | James King | Ospreys | Wales | 24-Jul-1990 | 26(301) |
| 20-May-2017 | Tyler Bleyedaal | Munster | New Zealand | 31-May-1990 | 26(355) |
| 20-May-2017 | Ashley Beck | Ospreys | Wales | 15-Apr-1990 | 27(35) |
| 19-May-2017 | Lewis Rawlins | Scarlets | Wales | 13-Apr-1990 | 27(36) |
| 20-May-2017 | CJ Stander | Munster | Ireland | 05-Apr-1990 | 27(45) |
| 20-May-2017 | Simon Zebo | Munster | Ireland | 16-Mar-1990 | 27(65) |
| 20-May-2017 | Daniel Biggar | Ospreys | Wales | 16-Oct-1989 | 27(216) |
| 19-May-2017 | Jack McGrath | Leinster | Ireland | 11-Oct-1989 | 27(220) |
| 20-May-2017 | Peter O'Mahony | Munster | Ireland | 17-Sep-1989 | 27(245) |
| 20-May-2017 | Justin Tipuric | Ospreys | Wales | 06-Aug-1989 | 27(287) |
| 20-May-2017 | Conor Murray | Munster | Ireland | 20-Apr-1989 | 28(30) |
| 20-May-2017 | Dave Kilcoyne | Munster | Ireland | 14-Dec-1988 | 28(157) |
| 20-May-2017 | Daniel Evans | Ospreys | Wales | 15-Nov-1988 | 28(186) |
| 20-May-2017 | John Ryan | Munster | Ireland | 02-Aug-1988 | 28(291) |
| 20-May-2017 | Scott Baldwin | Ospreys | Wales | 12-Jul-1988 | 28(312) |
| 19-May-2017 | Jon Davies | Scarlets | Wales | 05-Apr-1988 | 29(44) |
| 20-May-2017 | Kieron Fonotia | Ospreys | Samoa | 02-Feb-1988 | 29(108) |
| 20-May-2017 | Keith Earls | Munster | Ireland | 02-Oct-1987 | 29(231) |
| 19-May-2017 | Aaron Shingler | Scarlets | Wales | 07-Aug-1987 | 29(286) |
MD = Match date,
DOB = Date of birth,
A(D) = Age(days).