Additions
| from | Name | Pos | Team | Team | ||
|---|---|---|---|---|---|---|
| 07/1999 |  | Iraizoz | GK | |||
| 07/1999 | | Gurpegi | MF |  | Athletic Club U19 | Bilbao U19 |
| 07/1999 | | Iván Rodríguez | MF | | Athletic Club U19 | Bilbao U19 |
| 07/1999 | | Cuevas | FW | |||
| 07/1999 | | Gorka Sánchez | FW | | Athletic Club U19 | Bilbao U19 |
Departures
| from | Name | Pos | Team | Team | ||
|---|---|---|---|---|---|---|
| 01/2000 | | Gurpegi | MF |  | Athletic Club B | Bilbao B |
| 07/1999 | | Urko Macías | GK | | Athletic Club B | Bilbao B |
| 07/1999 | | Zubizarreta | DF | | Athletic Club B | Bilbao B |
| 07/1999 | | Esparza | MF |  | CD Izarra | CD Izarra |