Arminia Bielefeld (Bundesliga): every transfer in and out, fees paid and earned, squad market value, €16m spent and €15m earned.
| Date | Player | From | To | Fee |
|---|---|---|---|---|
| 2026-07-30 | Julian Kania | Arminia Bielefeld | De Graafschap Doetinchem | Free |
| 2026-07-16 | Christopher Lannert | Arminia Bielefeld | SV Darmstadt 98 | Free |
| 2026-07-01 | Jannik Rochelt | Hannover 96 | Arminia Bielefeld | €400k |
| 2026-07-01 | Henri Koudossou | FC Augsburg | Arminia Bielefeld | €500k |
| 2026-07-01 | Mika Schroers | Arminia Bielefeld | Alemannia Aachen | €150k |
| 2026-07-01 | Noah Joel Sarenren Bazee | Arminia Bielefeld | Waldhof Mannheim | Free |
| 2026-07-01 | Justin Lukas | Arminia Bielefeld | FC Gütersloh | Free |
| 2026-07-01 | Mael Corboz | Arminia Bielefeld | Grenoble | Free |
| 2026-07-01 | Max Lippert | Arminia Bielefeld | Köln II | Free |
| 2026-01-30 | Robin Knoche | 1. FC Nürnberg | Arminia Bielefeld | Free |
| 2026-01-27 | Vincent Ocansey | Arminia Bielefeld | Erzgebirge Aue | Loan |
| 2026-01-20 | Fabian Kunze | Arminia Bielefeld | Hansa Rostock | Loan |
| 2026-01-04 | Maximilian Bauer | Augsburg | Arm. Bielefeld | Loan |
| 2026-01-03 | Jannik Rochelt | Hannover 96 | Arminia Bielefeld | Loan |
| 2026-01-02 | Semir Telalovic | 1. FC Nürnberg | Arminia Bielefeld | Loan |
| 2026-01-01 | Julian Kania | Arminia Bielefeld | VfL Osnabrück | Loan |
| 2025-09-01 | Monju Momuluh | Hannover 96 | Arminia Bielefeld | €400k |
| 2025-08-29 | Arne Sicker | SV Elversberg | Arminia Bielefeld | Free |
| 2025-08-27 | Mika Schroers | Arminia Bielefeld | Alemannia Aachen | Loan |
| 2025-08-24 | Marius Wörl | Hannover 96 | Arminia Bielefeld | €1.5m |