Additions
| from | Name | Pos | Team | Team | ||
|---|---|---|---|---|---|---|
| 07/2018 |  | Alonso | DF |  | SCD Durango | Durango |
| 07/2018 | | Beñat Prados | MF |  | Athletic Club U19 | Bilbao U19 |
| 07/2018 | | Gorka Agirre | MF | | Athletic Club U19 | Bilbao U19 |
| 07/2018 | | Gorka Estrada | MF | | Athletic Club U19 | Bilbao U19 |
| 07/2018 | | Asier Parra | FW |  | Club Portugalete | Portugalete |
| 07/2018 |  | Ewan | FW | | Athletic Club U19 | Bilbao U19 |
| 07/2018 | | Solabarrieta | MA |
Departures
| from | Name | Pos | Team | Team | ||
|---|---|---|---|---|---|---|
| 12/2018 | | Solabarrieta | MA |  | Athletic Club B | Bilbao B |
| 07/2018 |  | Christophe Atangana | GK |  | SD Leioa | Leioa |
| 07/2018 | | Amorrortu | FW | | SCD Durango | Durango |
| 07/2018 | | Xabi Garai | FW |  | SD Gernika | Gernika |
| 07/2018 | | Asier Parra | FW | | SD Gernika | Gernika |
| 07/2018 | | Ibai Rodríguez | DF |  | Sodupe UC | Sodupe UC |
| 07/2018 | | Egiluz | MF | | SD Leioa | Leioa |
| 07/2018 | | Garai | MF | | SD Leioa | Leioa |
| 07/2018 | | Zarraga | MF | | Athletic Club B | Bilbao B |
| 07/2018 | | Andoni Tascón | FW | | Athletic Club B | Bilbao B |
| 07/2018 | | Morcillo | FW | | Athletic Club B | Bilbao B |