Transfers
Recent player movements in and out of the squad
| Date | Player | From | To | Type |
|---|---|---|---|---|
| 26.02.2026 | D. Ceylan | Kocaelispor | Kocaelispor | - |
| 30.01.2026 | Mahamadou Susoho Sissoho | Manchester City | Kocaelispor | Transfer |
| 29.01.2026 | Mahamadou Susoho Sissoho | Manchester City | Kocaelispor | Transfer |
| 01.11.2025 | E. Lawal | — | Kocaelispor | Return from loan |
| 01.11.2025 | Toheeb Lawal | — | Kocaelispor | Return from loan |
| 12.09.2025 | H. Keïta | Clermont Foot | Kocaelispor | Loan |
| 11.09.2025 | H. Keïta | Clermont Foot | Kocaelispor | Loan |
| 11.09.2025 | S. Dursun | — | Kocaelispor | Free Transfer |
| 10.09.2025 | S. Dursun | — | Kocaelispor | Free agent |
| 09.09.2025 | S. Dursun | — | Kocaelispor | Free agent |
| 08.09.2025 | B. Balogh | Parma | Kocaelispor | Loan |
| 07.09.2025 | B. Balogh | Parma | Kocaelispor | Loan |
| 06.09.2025 | H. Smolčić | Eintracht Frankfurt | Kocaelispor | Loan |
| 05.09.2025 | H. Smolčić | Eintracht Frankfurt | Kocaelispor | Loan |
| 01.09.2025 | D. Churlinov | Burnley | Kocaelispor | Transfer |
| 31.08.2025 | D. Churlinov | Burnley | Kocaelispor | Transfer |
| 22.08.2025 | O. Syrota | Dynamo Kyiv | Kocaelispor | Loan |
| 22.08.2025 | T. Bingöl | Besiktas | Kocaelispor | Free Transfer |
| 21.08.2025 | T. Bingöl | Besiktas | Kocaelispor | - |
| 21.08.2025 | O. Syrota | Dynamo Kyiv | Kocaelispor | Loan |
| 14.08.2025 | K. Linetty | Torino | Kocaelispor | Free Transfer |
| 13.08.2025 | C. Keles | Besiktas | Kocaelispor | Loan |
| 13.08.2025 | K. Linetty | Torino | Kocaelispor | Free agent |
| 12.08.2025 | C. Keles | Besiktas | Kocaelispor | Loan |
| 30.07.2025 | M. Wieteska | Cagliari | Kocaelispor | Loan |
| 29.07.2025 | M. Wieteska | Cagliari | Kocaelispor | Loan |
| 25.07.2025 | A. Dijksteel | — | Kocaelispor | Free Transfer |
| 24.07.2025 | A. Dijksteel | — | Kocaelispor | Free agent |
| 23.07.2025 | Serhat Oztasdelen | — | Kocaelispor | Transfer |
| 22.07.2025 | Serhat Oztasdelen | — | Kocaelispor | Transfer |
| 15.07.2025 | B. Petković | Dinamo Zagreb | Kocaelispor | Free agent |
| 09.07.2025 | M. Haïdara | Stade Brestois 29 | Kocaelispor | Free Transfer |
| 08.07.2025 | J. Nonge Boende | — | Kocaelispor | Free Transfer |
| 04.07.2025 | J. Nonge Boende | Juventus | Kocaelispor | Free agent |
| 03.07.2025 | Show | — | Kocaelispor | Loan |
| 01.07.2025 | H. Sarman | — | Kocaelispor | Back from Loan |
| 01.07.2025 | Ü. Ekşi | — | Kocaelispor | Back from Loan |
| 01.07.2025 | B. Yıldız | — | Kocaelispor | Back from Loan |
| 01.07.2025 | M. Haïdara | Stade Brestois 29 | Kocaelispor | Free agent |
| 01.07.2025 | F. Özyapı | — | Kocaelispor | Back from Loan |
| 01.07.2025 | D. Agyei | — | Kocaelispor | Free Transfer |
| 30.06.2025 | A. Jovanović | FK Partizan | Kocaelispor | Transfer |
| 29.06.2025 | U. Eksi | — | Kocaelispor | Return from loan |
| 29.06.2025 | B. Yildiz | — | Kocaelispor | Return from loan |
| 29.06.2025 | H. Sarman | — | Kocaelispor | Return from loan |
| 09.02.2025 | R. Rivas | — | Kocaelispor | Transfer |
| 07.02.2025 | R. Rivas | — | Kocaelispor | Transfer |
| 25.01.2025 | B. Şen | Galatasaray | Kocaelispor | Loan |
| 13.01.2025 | S. Yalçın | — | Kocaelispor | Transfer |
| 13.01.2025 | S. Yalçın | — | Kocaelispor | Transfer |