Bilbao Athletic: every transfer in and out, fees paid and earned, squad market value, €2.5m spent.
| Date | Player | From | To | Fee |
|---|---|---|---|---|
| 2025-07-01 | Alejandro Rego | Bilbao Athletic | Athletic Club | — |
| 2024-07-01 | Álex Padilla | Bilbao Athletic | Athletic Club | — |
| 2024-07-01 | Urko Izeta | Bilbao Athletic | Athletic Club | — |
| 2024-07-01 | Unai Egiluz | Bilbao Athletic | Athletic Club | — |
| 2024-07-01 | Mikel Jauregizar | Bilbao Athletic | Athletic Club | — |
| 2024-07-01 | Hugo Rincón | Bilbao Athletic | Athletic Club | — |
| 2024-07-01 | Adama Boiro | Bilbao Athletic | Athletic Club | — |
| 2024-01-24 | Adama Boiro | Osasuna B | Bilbao Athletic | €2m |
| 2023-07-01 | Unai Gómez | Bilbao Athletic | Athletic Club | — |
| 2023-07-01 | Mikel Jauregizar | CD Basconia | Bilbao Athletic | — |
| 2023-07-01 | Mikel Goti | Bilbao Athletic | Real Sociedad B | Free |
| 2023-07-01 | Aingeru Olabarrieta | Bilbao U19 | Bilbao Athletic | — |
| 2023-07-01 | Adu Ares | Bilbao Athletic | Athletic | — |
| 2023-01-19 | Urko Izeta | SD Eibar | Bilbao Athletic | — |
| 2022-07-06 | Álvaro Núñez | Bilbao Athletic | Barça Atlètic | Free |
| 2022-07-01 | Álex Padilla | CD Basconia | Bilbao Athletic | — |
| 2022-07-01 | Unai Gómez | CD Basconia | Bilbao Athletic | — |
| 2022-07-01 | Unai Egiluz | CD Basconia | Bilbao Athletic | — |
| 2022-07-01 | Nico Serrano | Bilbao Athletic | Athletic Club | — |
| 2022-07-01 | Julen Agirrezabala | Bilbao Athletic | Athletic Club | — |