Boston River (Primera División): every transfer in and out, fees paid and earned, squad market value, €3.1m spent and €6.4m earned.
| Date | Player | From | To | Fee |
|---|---|---|---|---|
| 2026-08-22 | Leo Suárez | UNAM Pumas | Boston River | Free |
| 2026-08-22 | Federico Dafonte | Boston River | Al Waab | Free |
| 2026-07-23 | Nicolás Siri | Montevideo City Torque | Boston River | Free |
| 2026-07-04 | Francisco Barrios | Boston River | CFR Cluj | Free |
| 2026-07-01 | Rodrigo Saravia | Ponte Preta | Boston River | Free |
| 2026-07-01 | Marcos Emmanuel Gómez Piñeiro | Boston River | Al Kharitiyath | €870k |
| 2026-02-14 | Francisco Martinicorena | Rentistas | Boston River | Free |
| 2026-02-03 | Marcos Emmanuel Gómez Piñeiro | Boston River | Al Kharitiyath | Loan |
| 2026-01-17 | Emanuel Beltrán | Boston River | Club Atletico Colón | Loan |
| 2026-01-14 | Yair González | Asociación Atlética Argentinos Juniors | Boston River | Loan |
| 2026-01-14 | Lucas Maximiliano Lemos Mayuncaldi | Boston River | Mushuc Runa SC | Loan |
| 2026-01-12 | Ernesto Exequiel Hernández Oncina | Boston River | Fénix | Free |
| 2026-01-01 | Francisco Bonfiglio | Miami FC II | Boston River | Free |
| 2026-01-01 | Agustín Aguirre | Nueva Chicago | Boston River | Free |
| 2025-08-27 | Lucas Maximiliano Lemos Mayuncaldi | Boston River | River Plate | Loan |
| 2025-08-26 | Francisco Barrios | Defensor Sporting | Boston River | Free |
| 2025-08-11 | Nicolás Campos | Boston River | Central Español | Free |
| 2025-08-08 | R. Rodríguez | Club Atlético Vélez Sársfield | Boston River | Loan |
| 2025-08-04 | Franco Suárez | Boston River | Racing | Free |
| 2025-08-01 | Rafael Haller | Nacional | Boston River | Loan |