| 3. Round | 10/09/2023 | CD Castellón | - | CF Intercity | 3:1 | ||||
| 5. Round | 23/09/2023 | Recreativo Huelva | - | CD Castellón | 0:3 | ||||
| 6. Round | 30/09/2023 | CD Castellón | - | Mérida AD | 5:1 | ||||
| 7. Round | 07/10/2023 | CD Castellón | - | Real Madrid Castilla | 4:1 | ||||
| 8. Round | 15/10/2023 | AD Ceuta FC | - | CD Castellón | 1:3 | ||||
| 9. Round | 22/10/2023 | CD Castellón | - | Atlético Madrid B | 2:0 | ||||
| 10. Round | 28/10/2023 | San Fernando CD | - | CD Castellón | 2:0 |  |
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| 11. Round | 05/11/2023 | CD Castellón | - | CD Alcoyano | 2:0 | ||||
| 12. Round | 12/11/2023 | Recreativo Granada | - | CD Castellón | 0:3 | ||||
| 13. Round | 19/11/2023 | CD Castellón | - | Atlético Baleares | 4:2 | ||||
| 14. Round | 26/11/2023 | UD Ibiza | - | CD Castellón | 2:0 | |
Puerto Rico