Union SG U23: every transfer in and out, fees paid and earned, squad market value, €50k spent.
| Date | Player | From | To | Fee |
|---|---|---|---|---|
| 2025-07-11 | Mohamed Asaidi | Union SG U23 | C. Budejovice | Free |
| 2025-07-01 | Mathis Roete | Cercle U18 | Union SG U23 | Free |
| 2025-07-01 | Cristian Makaté | Union SG U23 | Union SG | — |
| 2024-07-01 | Yari Stevens | Jong KAA Gent | Union SG U23 | Free |
| 2024-07-01 | Tiago Gomes | Union SG U23 | Schaerbeek | Free |
| 2024-07-01 | Sada Diallo | RWDM | Union SG U23 | Free |
| 2024-07-01 | Mamadou Traoré | Union SG U23 | Union SG | — |
| 2023-08-31 | Mamadou Traoré | Union SG U23 | Castellón | Loan |
| 2023-08-23 | Nathan Huygevelde | Union SG U23 | Union SG | Loan |
| 2023-07-01 | Tiago Gomes | KAC Betekom | Union SG U23 | Free |
| 2023-07-01 | Noa Louche | Union SG U18 | Union SG U23 | — |
| 2023-07-01 | Mamadou Traoré | Without Club | Union SG U23 | — |
| 2023-07-01 | Daniel Tshilanda Kabongo | Union SG U18 | Union SG U23 | — |
| 2023-01-12 | Samuel Chukwudi | Union SG U23 | HB Tórshavn | Free |
| 2022-08-15 | Cristian Makaté | Ambrosiana | Union SG U23 | Free |
| 2022-07-01 | Nathan Huygevelde | Union SG U18 | Union SG U23 | — |
| 2022-07-01 | Mohamed Asri | Union SG U18 | Union SG U23 | — |
| 2022-07-01 | Joachim Imbrechts | Union SG U23 | Union SG | — |
| 2022-06-18 | Samuel Chukwudi | Union SG U21 | HB Tórshavn | Loan |
| 2022-01-18 | Samuel Chukwudi | HB Tórshavn | Union SG U21 | €50k |