Athletic Bilbao (Laliga): every transfer in and out, fees paid and earned, squad market value, €127m spent and €190m earned.
| Date | Player | From | To | Fee |
|---|---|---|---|---|
| 2026-07-01 | Iñigo Lekue | Athletic Club | Retired | — |
| 2025-11-01 | Selton Sánchez | CD Basconia | Athletic Club | — |
| 2025-09-01 | Unai Vencedor | Athletic Club | Levante | Loan |
| 2025-09-01 | Aymeric Laporte | Al-Nassr | Athletic Club | €10m |
| 2025-07-29 | Hugo Rincón | Athletic Club | Girona | Loan |
| 2025-07-28 | Álvaro Djaló | Athletic Bilbao | Al Gharafa | Loan |
| 2025-07-28 | Álvaro Djaló | Athletic Club | Al-Gharafa | Loan |
| 2025-07-22 | Jesús Areso | CA Osasuna | Athletic Club | €12m |
| 2025-07-11 | Julen Agirrezabala | Athletic Club | Valencia | Loan |
| 2025-07-01 | Óscar de Marcos | Athletic Club | Retired | — |
| 2025-07-01 | Robert Navarro | RCD Mallorca | Athletic Club | Free |
| 2025-07-01 | Alejandro Rego | Bilbao Athletic | Athletic Club | — |
| 2025-02-01 | Maroan Sannadi | Alavés | Athletic Club | €3m |
| 2025-01-31 | Nico Serrano | Athletic Club | Sporting Gijón | Loan |
| 2025-01-17 | Ander Herrera | Athletic Club | Boca Juniors | €400k |
| 2025-01-09 | Álex Padilla | Athletic Club | UNAM Pumas | Loan |
| 2024-08-29 | Unai Egiluz | Athletic Club | CD Mirandés | Loan |
| 2024-08-28 | Unai Núñez | Celta de Vigo | Athletic Club | Loan |
| 2024-08-11 | Hugo Rincón | Athletic Club | CD Mirandés | Loan |
| 2024-08-08 | Urko Izeta | Athletic Club | CD Mirandés | Loan |