Union Saint-Gilloise (Jupiler Pro League): every transfer in and out, fees paid and earned, squad market value, €73m spent and €152m earned.
| Date | Player | From | To | Fee |
|---|---|---|---|---|
| 2026-07-01 | Ondrej Kricfalusi | Banik Ostrava | Union SG | €5m |
| 2026-07-01 | Nikki Havenaar | SV Ried | Union SG | €400k |
| 2026-07-01 | Guillaume François | Union SG | Retired | — |
| 2026-07-01 | Christian Burgess | Union SG | Without Club | — |
| 2026-01-28 | Cristian Makaté | Union SG | La Louvière | Loan |
| 2026-01-24 | Mathias Rasmussen | Union SG | St. Pauli | €1m |
| 2026-01-14 | Sofiane Boufal | Union SG | Le Havre AC | Free |
| 2026-01-13 | Massiré Sylla | Lyn | Union SG | €800k |
| 2026-01-13 | Besfort Zeneli | Elfsborg | Union SG | €3.4m |
| 2026-01-03 | Mateo Biondic | Eintracht Trier | Union SG | €220k |
| 2025-10-13 | Jens Teunckens | Without Club | Union SG | — |
| 2025-09-05 | Henok Teklab | Union SG | OH Leuven | Free |
| 2025-09-03 | Ivan Pavlic | Paços Ferreira | Union SG | €250k |
| 2025-09-02 | Louis Patris | Sint-Truiden | Union SG | €3.8m |
| 2025-09-01 | Rob Schoofs | KV Mechelen | Union SG | €1.4m |
| 2025-09-01 | Lazare Amani | Union SG | Without Club | — |
| 2025-09-01 | Charles Vanhoutte | Union SG | Nice | €6m |
| 2025-09-01 | Alessio Castro-Montes | Union SG | 1.FC Köln | €2m |
| 2025-08-12 | Guilherme Smith | Kalju FC | Union SG | €400k |
| 2025-07-31 | Franjo Ivanović | Union SG | Benfica | €23m |