| MD | Players | Club | Nationality | DOB | A(D) |
|---|---|---|---|---|---|
| 14-Oct-2017 |  Rio Dyer | Gwent Dragons | Wales | 21-Dec-1999 | 17(298) |
| 22-Oct-2017 |  Alex Cant | Cornish Pirates | England | 07-Nov-1999 | 17(350) |
| 15-Dec-2017 |  George Kloska | Bristol Bears | England | 16-Nov-1999 | 18(30) |
| 16-Dec-2017 | Taine Basham | Gwent Dragons | Wales | 02-Nov-1999 | 18(45) |
| 13-Jan-2018 |  Corey Baldwin | Scarlets | Wales | 13-Oct-1999 | 18(93) |
| 19-Jan-2018 | Niall Murray | Connacht | Ireland | 13-Oct-1999 | 18(99) |
| 14-Oct-2017 | James Dun | Bristol Bears | England | 07-Jul-1999 | 18(100) |
| 16-Dec-2017 |  Corey Howells | Cardiff Blues | Wales | 16-Jul-1999 | 18(154) |
| 16-Dec-2017 | Cai Evans | Ospreys | Wales | 23-Jun-1999 | 18(177) |
| 16-Dec-2017 | Sam Wolstenholme | Leeds Tykes | England | 21-Jun-1999 | 18(179) |
| 13-Jan-2018 | Dylan Tierney | Connacht | Ireland | 20-Jun-1999 | 18(208) |
| 13-Jan-2018 |  Nick Dolly | Rotherham Titans | England | 11-Jun-1999 | 18(217) |
| 14-Oct-2017 |  Angus Kernohan | Ulster | Ireland | 02-Mar-1999 | 18(227) |
| 13-Jan-2018 | Dafydd Smith | Cardiff Blues | Wales | 23-May-1999 | 18(236) |
| 14-Oct-2017 | Ryan Conbeer | Scarlets | Wales | 05-Feb-1999 | 18(252) |
| 21-Oct-2017 | Tom Willis | Rotherham Titans | England | 18-Jan-1999 | 18(277) |
| 13-Oct-2017 | Harry Davey | Leeds Tykes | England | 21-Dec-1998 | 18(297) |
| 14-Oct-2017 | Joe Dunleavy | Ulster | Ireland | 22-Dec-1998 | 18(297) |
| 21-Oct-2017 | Will Porter | Rotherham Titans | England | 14-Dec-1998 | 18(312) |
| 19-Jan-2018 | Callum Carson | Ospreys | Wales | 13-Mar-1999 | 18(313) |
| 14-Oct-2017 | Will Jones | Ospreys | Wales | 03-Dec-1998 | 18(316) |
| 16-Dec-2017 | Lennon Greggains | Gwent Dragons | Wales | 20-Jan-1999 | 18(331) |
| 22-Oct-2017 | Matt Dalton | Ulster | Ireland | 16-Nov-1998 | 18(341) |
| 17-Dec-2017 | Tom Rogers | Scarlets | Wales | 17-Dec-1998 | 19(0) |
| 14-Oct-2017 | Rhys Henry | Ospreys | Wales | 08-Sep-1998 | 19(36) |
| 13-Jan-2018 | Charlie Chapman | Hartpury College | Scotland | 01-Dec-1998 | 19(43) |
| 20-Jan-2018 | Josh Reynolds | Gwent Dragons | Wales | 01-Dec-1998 | 19(50) |
| 17-Dec-2017 | Lewis Ellis-Jones | Scarlets | Wales | 27-Oct-1998 | 19(51) |
| 12-Jan-2018 | Matthew Agnew | Ulster | Ireland | 20-Nov-1998 | 19(53) |
| 13-Jan-2018 |  Jack Aungier | Leinster | Ireland | 20-Nov-1998 | 19(54) |
| 14-Oct-2017 | Will Davies-King | Cardiff Blues | Wales | 28-Jul-1998 | 19(78) |
| 16-Dec-2017 | Tom O'Toole | Ulster | Ireland | 23-Sep-1998 | 19(84) |
| 17-Dec-2017 | Dan Davis | Scarlets | Wales | 17-Sep-1998 | 19(91) |
| 14-Oct-2017 | Dane Blacker | Cardiff Blues | Wales | 06-Jul-1998 | 19(100) |
| 19-Jan-2018 | Owen Lloyd | Cardiff Blues | Wales | 07-Oct-1998 | 19(104) |
| 16-Dec-2017 | Morgan Morris | Ospreys | Wales | 28-Aug-1998 | 19(110) |
| 21-Oct-2017 | Michael Silvester | Leinster | Ireland | 04-Jun-1998 | 19(139) |
| 14-Oct-2017 |  Sam Jones | Doncaster Knights | England | 22-May-1998 | 19(145) |
| 13-Jan-2018 | Alun Lawrence | Cardiff Blues | Wales | 12-Aug-1998 | 19(154) |
| 22-Oct-2017 | James Newey | Bristol Bears | Ireland | 03-May-1998 | 19(172) |
| 30-Mar-2018 |  Jack O'Sullivan | Munster | Ireland | 01-Oct-1998 | 19(180) |
| 14-Oct-2017 | Ronan Coffey | Munster | Ireland | 09-Apr-1998 | 19(188) |
| 13-Jan-2018 | Max Kearney | Leinster | Ireland | 05-Jul-1998 | 19(192) |
| 21-Oct-2017 | Joe Goodchild | Gwent Dragons | Wales | 12-Apr-1998 | 19(192) |
| 14-Oct-2017 | Ioan Nicholas | Scarlets | Wales | 03-Apr-1998 | 19(194) |
| 14-Oct-2017 | Hugh O'Sullivan | Leinster | Ireland | 24-Feb-1998 | 19(232) |
| 21-Oct-2017 | Tommy O'Brien | Leinster | Ireland | 20-Feb-1998 | 19(243) |
| 22-Oct-2017 | Jonny Stewart | Ulster | Ireland | 20-Feb-1998 | 19(244) |
| 16-Dec-2017 | Dave McCarthy | Munster | Ireland | 15-Apr-1998 | 19(245) |
| 14-Oct-2017 | Ehize Edevbalo-Ehizode | Bristol Bears | England | 08-Feb-1998 | 19(248) |
MD = Match date,
DOB = Date of birth,
A(D) = Age(days).