| 6. Round | 08/10/2023 | CD Alavés B | - | Athletic Club B | 0:2 | ||||
| 9. Round | 29/10/2023 | Athletic Club B | - | AD San Juan | 3:1 | ||||
| 10. Round | 04/11/2023 | Arenas de Getxo | - | Athletic Club B | 0:3 | ||||
| 14. Round | 03/12/2023 | Náxara CD | - | Athletic Club B | 1:2 | ||||
| 15. Round | 09/12/2023 | Athletic Club B | - | Real Sociedad C | 3:0 | ||||
| 16. Round | 17/12/2023 | SD Gernika | - | Athletic Club B | 1:1 | ||||
| 17. Round | 06/01/2024 | Athletic Club B | - | CD Brea | 3:0 | ||||
| 18. Round | 14/01/2024 | Athletic Club B | - | UD Logroñés | 0:0 | ||||
| 19. Round | 21/01/2024 | Utebo FC | - | Athletic Club B | 0:0 | ||||
| 21. Round | 03/02/2024 | Athletic Club B | - | CD Izarra | 2:1 | ||||
| 22. Round | 10/02/2024 | CD Valle de Egüés | - | Athletic Club B | 0:2 | ||||
| 24. Round | 25/02/2024 | Real Zaragoza B | - | Athletic Club B | 2:2 | ||||
| 25. Round | 02/03/2024 | Athletic Club B | - | UD Mutilvera | 3:1 | ||||
| 28. Round | 24/03/2024 | Barakaldo CF | - | Athletic Club B | 1:2 | ||||
| 30. Round | 05/04/2024 | CD Tudelano | - | Athletic Club B | 1:2 | ||||
| 31. Round | 13/04/2024 | Athletic Club B | - | Náxara CD | 4:0 | ||||
| 33. Round | 28/04/2024 | Athletic Club B | - | SD Gernika | 3:1 | ||||
| 34. Round | 05/05/2024 | CD Brea | - | Athletic Club B | 0:5 |  |
Spain