Cardiff U18: every transfer in and out, fees paid and earned, squad market value.
| Date | Player | From | To | Fee |
|---|---|---|---|---|
| 2024-07-01 | Ronan Kpakio | Cardiff U18 | Cardiff U21 | — |
| 2024-07-01 | Dylan Lawlor | Cardiff U18 | Cardiff U21 | — |
| 2023-07-01 | Ronan Kpakio | Cardiff City Yo | Cardiff U18 | — |
| 2022-07-01 | Joel Colwill | Cardiff U18 | Cardiff U21 | — |
| 2022-07-01 | Dylan Lawlor | Cardiff City Yo | Cardiff U18 | — |
| 2021-07-01 | Joel Colwill | Cardiff City Yo | Cardiff U18 | — |
| 2021-07-01 | Eli King | Cardiff U18 | Cardiff U21 | — |
| 2021-01-01 | Rubin Colwill | Cardiff U18 | Cardiff | — |
| 2020-07-01 | Isaak Davies | Cardiff U18 | Cardiff City U23 | — |
| 2019-07-01 | Eli King | Cardiff City Yo | Cardiff U18 | — |
| 2018-07-01 | Rubin Colwill | Cardiff City Yo | Cardiff U18 | — |
| 2018-07-01 | Isaak Davies | Cardiff City Yo | Cardiff U18 | — |
| 2017-07-01 | Mark Harris | Cardiff U18 | Cardiff City U23 | — |
| 2015-07-01 | Mark Harris | Cardiff City Yo | Cardiff U18 | — |
| 2013-07-01 | Declan John | Cardiff U18 | Cardiff | — |