When must you indicate?

You must indicate when leaving a roundabout, not when entering it. This is because German traffic rules prioritize giving a clear signal of your exit intention so that other drivers can anticipate your movement and adjust their behavior accordingly. When entering a roundabout, signaling is generally not required since you are merging into the circular flow, but you must yield to traffic already on the roundabout. Signaling when leaving the roundabout helps avoid confusion and enhances safety for other road users.