Additions
| from | Name | Pos | Team | Team | ||
|---|---|---|---|---|---|---|
| 02/2021 |  | Unai Ayala | GK |  | SD Eibar B | SD Eibar B |
| 01/2021 | | Aleix García | MF |  | FC Dinamo Bucureşti | Dinamo Bucurest |
| 01/2021 | | Roncal | FW | |||
| 10/2020 | | Álex Pozo | FW |  | Sevilla FC | Sevilla |
| 10/2020 | | Bryan Gil | FW | | Sevilla FC | Sevilla |
| 09/2020 |  | Yoshinori Mutō | FW |  | Newcastle United | Newcastle |
| 09/2020 |  | Kévin Rodrigues | DF |  | Real Sociedad | Real Sociedad |
| 09/2020 | | Unai Arieta | FW | |||
| 09/2020 | | Recio | MF |  | CD Leganés | Leganés |
| 08/2020 |  | Damian Kądzior | MF |  | Dinamo Zagreb | Din. Zagreb |
| 08/2020 | | Jordi Calavera | DF |  | Girona FC | Girona |
| 08/2020 | | Magunagoitia | GK | |||
| 08/2020 | | Eñaut Mendia | FW |  | CD Vitoria | CD Vitoria |
| 07/2020 | | José Martínez | DF |  | Granada CF | Granada CF |
| 07/2020 | | Roberto Olabe | MF |  | CD Extremadura | CD Extremadura |
| 07/2020 | | Nano Mesa | FW |  | Cádiz CF | Cádiz |
| 07/2020 | | Unai Dufur | DF |
Departures
| from | Name | Pos | Team | Team | ||
|---|---|---|---|---|---|---|
| 01/2021 | | Damian Kądzior | MF |  | Alanyaspor | Alanyaspor |
| 01/2021 | | Roberto Olabe | MF |  | CD Tondela | CD Tondela |
| 01/2021 | | José Martínez | DF |  | FC Dallas | FC Dallas |
| 09/2020 | | Miguel Marí | FW |  | Orihuela CF | Orihuela CF |
| 09/2020 | | Jordi Calavera | DF | | Girona FC | Girona |
| 09/2020 |  | Gonzalo Escalante | MF |  | Lazio Roma | Lazio |
| 08/2020 | | Nano Mesa | FW | | Cádiz CF | Cádiz |
| 07/2020 |  | Charles | FW |  | Pontevedra CF | Pontevedra CF |
| 07/2020 |  | Sebastián Cristóforo | MF |  | ACF Fiorentina | Fiorentina |
| 07/2020 |  | Fabián Orellana | FW |  | Real Valladolid | Valladolid |
| 07/2020 | | Ekhi Bravo | DF |  | Real Unión | Real Unión |