Additions
| from | Name | Pos | Team | Team | ||
|---|---|---|---|---|---|---|
| 07/2003 |  | Fernando Amorebieta | DF | |||
| 07/2003 |  | Gago | DF | |||
| 07/2003 | | Garmendia | MF | |||
| 07/2003 | | Mikel Rico | MF | |||
| 07/2003 | | Tyson | MF | |||
| 07/2003 | | Llorente | FW |  | Athletic Club U19 | Bilbao U19 |
Departures
| from | Name | Pos | Team | Team | ||
|---|---|---|---|---|---|---|
| 07/2003 | | Goikoetxea | DF |  | Athletic Club B | Bilbao B |
| 07/2003 | | Tarantino | DF | | Athletic Club B | Bilbao B |
| 07/2003 | | Ustaritz | DF | | Athletic Club B | Bilbao B |
| 07/2003 | | Ibon Gutiérrez | MF | | Athletic Club B | Bilbao B |
| 07/2003 | | Mikel Martins | MF | | Athletic Club B | Bilbao B |
| 07/2003 | | Paredes | MF | | Athletic Club B | Bilbao B |