Diamond Harbour (I-League): every transfer in and out, fees paid and earned, squad market value.
| Date | Player | From | To | Fee |
|---|---|---|---|---|
| 2026-08-04 | Bryce Miranda | Diamond Harbour | Chennaiyin FC | Free |
| 2026-07-22 | Antonio Moyano | Diamond Harbour | FC United | Free |
| 2026-01-30 | Player | Diamond Harbour | Persis Solo | Free |
| 2025-08-25 | Sunday Afolabi | Perak FA | Diamond Harbour | Free |
| 2025-08-22 | Bryce Miranda | Kerala Blasters | Diamond Harbour | Free |
| 2025-07-27 | Holi Charan Narzary | Bengaluru FC | Diamond Harbour | Loan |
| 2025-07-25 | Luka Majcen | Punjab FC | Diamond Harbour | Free |
| 2025-07-23 | Mikel Kortazar | SD Amorebieta | Diamond Harbour | Free |
| 2025-07-21 | Wahengbam Angousana Luwang | Mohammedan | Diamond Harbour | Free |
| 2025-07-20 | Wungyanyg Muirang | Jamshedpur | Diamond Harbour | Free |
| 2025-07-16 | Samuel Lalmuanpuia | Aizawl | Diamond Harbour | Free |
| 2025-07-09 | Player | Perak FA | Diamond Harbour | Free |
| 2025-07-01 | Player | SAT | Diamond Harbour | Free |
| 2025-06-28 | Paul Ramfangzauva | Chanmari | Diamond Harbour | Free |
| 2025-06-25 | Mirshad Michu | FC United | Diamond Harbour | Free |
| 2025-06-20 | Melroy Assisi | Punjab FC | Diamond Harbour | Free |
| 2025-06-01 | R Ramdinthara | Gokulam | Diamond Harbour | Free |
| 2025-06-01 | Sairuat Kima | Sporting Goa | Diamond Harbour | Free |
| 2025-01-01 | Chirag Bhujel | Inter Kashi | Diamond Harbour | Loan |
| 2025-01-01 | Player | Real Kashmir | Diamond Harbour | Free |