Antiguoko U19: every transfer in and out, fees paid and earned, squad market value.
| Date | Player | From | To | Fee |
|---|---|---|---|---|
| 2020-07-17 | Mikel Rodriguez | Antiguoko U19 | R. Sociedad U19 | Free |
| 2018-07-01 | Julen Agirrezabala | Antiguoko U19 | Bilbao U19 | — |
| 2017-07-01 | Julen Agirrezabala | Antiguoko Yth | Antiguoko U19 | — |
| 2017-07-01 | Jon Ander Olasagasti | Antiguoko U19 | R. Sociedad U19 | — |
| 2015-07-01 | Jon Ceberio | Antiguoko U19 | Bolton U21 | — |
| 2014-07-01 | Gorka Guruzeta | Antiguoko U19 | Bilbao U19 | — |