| MD | Players | Club | Nationality | DOB | A(D) |
|---|---|---|---|---|---|
| 17-Dec-2016 |  Ryan Conbeer | Scarlets | Wales | 05-Feb-1999 | 17(316) |
| 23-Oct-2016 |  Will Jones | Ospreys | Wales | 03-Dec-1998 | 17(325) |
| 15-Oct-2016 | Charlie Davies | Ospreys | Wales | 15-Aug-1998 | 18(62) |
| 21-Jan-2017 | Chris Coleman | Gwent Dragons | Wales | 31-Aug-1998 | 18(144) |
| 14-Jan-2017 |  Dane Blacker | Cardiff Blues | Wales | 06-Jul-1998 | 18(193) |
| 15-Oct-2016 | Ioan Nicholas | Scarlets | Wales | 03-Apr-1998 | 18(196) |
| 13-Jan-2017 |  Ben White | Doncaster Knights | Scotland | 27-May-1998 | 18(232) |
| 10-Dec-2016 | Jack Pope | Ospreys | Wales | 21-Apr-1998 | 18(234) |
| 11-Dec-2016 | Joe Goodchild | Gwent Dragons | Wales | 12-Apr-1998 | 18(244) |
| 11-Dec-2016 | Max Williams | Gwent Dragons | Wales | 02-Apr-1998 | 18(254) |
| 15-Oct-2016 |  Tom Parton | London Irish | England | 02-Feb-1998 | 18(256) |
| 11-Dec-2016 | Matt Williams | London Irish | England | 16-Mar-1998 | 18(271) |
| 11-Dec-2016 | Jack Cooke | London Irish | Ireland | 18-Feb-1998 | 18(297) |
| 15-Oct-2016 | Owen Lane | Cardiff Blues | Wales | 20-Dec-1997 | 18(300) |
| 15-Oct-2016 |  Gavin Coombes | Munster | Ireland | 11-Dec-1997 | 18(309) |
| 15-Oct-2016 | Pat Lewis | Gwent Dragons | Wales | 25-Nov-1997 | 18(325) |
| 13-Jan-2017 |  Jonny Stewart | Ulster | Ireland | 20-Feb-1998 | 18(328) |
| 15-Oct-2016 | Joe Cokanasiga | London Irish | England | 15-Nov-1997 | 18(335) |
| 14-Jan-2017 | Rhys Carre | Cardiff Blues | Wales | 08-Feb-1998 | 18(341) |
| 15-Oct-2016 |  Jack Kelly | Leinster | Ireland | 26-Oct-1997 | 18(355) |
| 21-Jan-2017 | Sean Masterson | Connacht | Ireland | 27-Jan-1998 | 18(360) |
| 15-Oct-2016 | James Ratti | Ospreys | Wales | 14-Oct-1997 | 19(1) |
| 11-Dec-2016 | Jacob Atkins | London Irish | England | 05-Dec-1997 | 19(6) |
| 21-Jan-2017 | Jared Rosser | Gwent Dragons | Wales | 31-Dec-1997 | 19(21) |
| 15-Oct-2016 | Luke Carty | Connacht | United States | 24-Sep-1997 | 19(21) |
| 15-Oct-2016 | Shane Lewis-Hughes | Cardiff Blues | Wales | 20-Sep-1997 | 19(25) |
| 07-Jan-2017 | Fineen Wycherley | Munster | Ireland | 11-Dec-1997 | 19(27) |
| 15-Oct-2016 | Declan Smith | Scarlets | Wales | 14-Sep-1997 | 19(31) |
| 15-Oct-2016 | Will Talbot-Davies | Gwent Dragons | Wales | 11-Sep-1997 | 19(34) |
| 15-Oct-2016 | Ellis Shipp | Gwent Dragons | Wales | 14-Aug-1997 | 19(62) |
| 13-Jan-2017 | Alex McHenry | Munster | Ireland | 07-Oct-1997 | 19(98) |
| 15-Oct-2016 | Kieron Assiratti | Cardiff Blues | Wales | 30-Jun-1997 | 19(107) |
| 15-Oct-2016 | Connor Edwards | Gwent Dragons | Wales | 28-Jun-1997 | 19(109) |
| 14-Jan-2017 | Cameron Lewis | Cardiff Blues | Wales | 24-Sep-1997 | 19(112) |
| 10-Dec-2016 | Phil Jones | Ospreys | Wales | 09-Aug-1997 | 19(123) |
| 10-Dec-2016 | Calvin Nash | Munster | Ireland | 08-Aug-1997 | 19(124) |
| 15-Oct-2016 | Matthew Aubrey | Ospreys | Wales | 04-Jun-1997 | 19(133) |
| 14-Jan-2017 | Calum Bradbury | Cardiff Blues | Wales | 01-Sep-1997 | 19(135) |
| 15-Oct-2016 |  George Cox | Nottingham | England | 02-Jun-1997 | 19(135) |
| 14-Jan-2017 | Nathan Hudd | Gwent Dragons | Wales | 22-Aug-1997 | 19(145) |
| 14-Jan-2017 | Cillian Gallagher | Connacht | Ireland | 23-Jul-1997 | 19(175) |
| 10-Dec-2016 | Jordan Larmour | Leinster | Ireland | 10-Jun-1997 | 19(183) |
| 15-Oct-2016 | Kieran Williams | Ospreys | Wales | 12-Apr-1997 | 19(186) |
| 15-Oct-2016 | John Foley | Munster | Ireland | 03-Apr-1997 | 19(195) |
| 14-Oct-2016 | Jonny McPhillips | Ulster | Ireland | 13-Mar-1997 | 19(215) |
| 14-Jan-2017 |  Josh Caulfield | Cornish Pirates | England | 09-Jun-1997 | 19(219) |
| 14-Jan-2017 | Max Wright | Leeds Tykes | England | 24-May-1997 | 19(235) |
| 15-Oct-2016 | Arwel Robson | Gwent Dragons | Wales | 21-Feb-1997 | 19(236) |
| 15-Oct-2016 |  Robbie Nairn | London Welsh | Scotland | 18-Feb-1997 | 19(239) |
| 22-Oct-2016 | Robert Lyttle | Ulster | Ireland | 28-Jan-1997 | 19(267) |
MD = Match date,
DOB = Date of birth,
A(D) = Age(days).