The Danube Bike Path is comfortable in 12 Stages to be completed. Four stages in Baden-Württemberg and eight stages in Bavaria.
Below you will find the individual stage suggestions starting in Donaueschingen at the source of the Danube (stage 1) to after Passau (Stage 12).
After Passau the Danube leaves Germany, then the Danube Cycle Path continues in Austria (Link) Further.