| MD | Players | Nationality | DOB | A(D) |
|---|---|---|---|---|
| 16-Dec-2017 | Werner Kruger | South Africa | 23-Jan-1985 | 32(327) |
| 21-Apr-2018 | John Barclay | Scotland | 24-Sep-1986 | 31(210) |
| 21-Apr-2018 | Ken Owens | Wales | 03-Jan-1987 | 31(109) |
| 21-Apr-2018 | Aaron Shingler | Wales | 07-Aug-1987 | 30(258) |
| 21-Apr-2018 | Hadleigh Parkes | Wales | 05-Oct-1987 | 30(199) |
| 20-Oct-2017 | Jon Davies | Wales | 05-Apr-1988 | 29(198) |
| 21-Apr-2018 | Leigh Halfpenny | Wales | 22-Dec-1988 | 29(120) |
| 21-Apr-2018 | David Bulbring | South Africa | 12-Sep-1989 | 28(221) |
| 21-Apr-2018 | Gareth Davies | Wales | 18-Aug-1990 | 27(246) |
| 21-Apr-2018 | Scott Williams | Wales | 10-Oct-1990 | 27(193) |
| 20-Oct-2017 | Lewis Rawlins | Wales | 13-Apr-1990 | 27(190) |
| 21-Apr-2018 | James Davies | Wales | 25-Oct-1990 | 27(178) |
| 16-Dec-2017 | Johnny McNicholl | Wales | 24-Sep-1990 | 27(83) |
| 20-Oct-2017 | Jake Ball | Wales | 21-Jun-1991 | 26(122) |
| 21-Apr-2018 | Rob Evans | Wales | 14-Apr-1992 | 26(7) |
| 20-Jan-2018 | Tom Prydie | Wales | 23-Feb-1992 | 25(332) |
| 09-Dec-2017 | Wyn Jones | Wales | 26-Feb-1992 | 25(287) |
| 21-Apr-2018 | Tadhg Beirne | Ireland | 01-Aug-1992 | 25(263) |
| 16-Dec-2017 | Steven Cummins | Australia | 29-Mar-1992 | 25(262) |
| 21-Apr-2018 | Samson Lee | Wales | 30-Nov-1992 | 25(142) |
| 15-Oct-2017 | Aled Davies | Wales | 19-Jul-1992 | 25(88) |
| 21-Apr-2018 | Rhys Patchell | Wales | 17-May-1993 | 24(339) |
| 30-Mar-2018 | Paul Asquith | Australia | 08-Dec-1993 | 24(112) |
| 21-Apr-2018 | Steffan Evans | Wales | 01-Sep-1994 | 23(232) |
| 16-Dec-2017 | Will Boyde | Wales | 15-Dec-1994 | 23(1) |
| 15-Oct-2017 | Ryan Elias | Wales | 07-Jan-1995 | 22(282) |
| 21-Apr-2018 | Daniel Jones | Wales | 07-Jan-1996 | 22(105) |
| 15-Oct-2017 | Josh Macleod | Wales | 27-Oct-1996 | 20(353) |
MD = Match date,
DOB = Date of birth,
A(D) = Age(days).