Real Unión: every transfer in and out, fees paid and earned, squad market value.
| Date | Player | From | To | Fee |
|---|---|---|---|---|
| 2024-07-10 | Javi Domínguez | Celta Fortuna | Real Unión | Free |
| 2024-07-03 | Iker Bilbao | Alcorcón | Real Unión | Free |
| 2024-02-01 | Tommi O'Reilly | Aston Villa U21 | Real Unión | Loan |
| 2024-02-01 | Josh Feeney | Aston Villa U21 | Real Unión | Loan |
| 2023-08-01 | Jon Aramburu | Real Unión | Real Sociedad B | — |
| 2023-07-30 | Marc Vales | Real Unión | CE Europa | Free |
| 2023-02-13 | Marc Vales | Without Club | Real Unión | — |
| 2023-01-20 | Shinichi Chan | Kitchee | Real Unión | Loan |
| 2022-08-25 | Antonio Espigares | Villarreal CF B | Real Unión | Loan |
| 2022-08-08 | Giorgi Gagua | Alavés B | Real Unión | Loan |
| 2022-07-30 | Victor Parada | Alavés B | Real Unión | Loan |
| 2022-07-20 | Jon Aramburu | Dep. La Guaira | Real Unión | — |
| 2022-07-04 | Patrick Sequeira | Real Unión | CD Lugo | Free |
| 2020-09-09 | Patrick Sequeira | Real Unión | Celta Vigo B | Loan |
| 2019-07-20 | Jon Ceberio | Real Unión | UD Melilla | Free |
| 2019-07-01 | Patrick Sequeira | Saprissa | Real Unión | Free |
| 2018-07-01 | Jon Ceberio | Real Sociedad C | Real Unión | Free |
| 2017-08-21 | Patrick Sequeira | Saprissa | Real Unión | Loan |
| 2016-07-09 | Andoni Gorosabel | Real Sociedad B | Real Unión | Loan |
| 2012-07-01 | Yuri Berchiche | Real Unión | Real Sociedad | Free |