Guide books and maps covering the Danube in Eastern Europe
While English as a second language is gaining importence in the region, German is occasionally understood by elder residents. If you don't speak German, you got one more reason to bring a good map.
Guide books for Slovakia and Hungary (Vienna to Budapest)
There are two guide books available: the "Danube Bike Trail 3" guide book (by Esterbauer) and the "The Danube Cycleway, Vol. 1" guide book (by Cicerone). We recommend getting the "Danube Bike Trail 3". It provides useful maps at a scale of 1:75,000, route instructions and hints as well as lists of accommodations and camp sites along the cycle path. Your map will be crucial as sign-posting along the way is not perfectly in place yet.
The two books cover the cycle paths up to Budapest. See here for the Danube cycle path beyond Budapest:
Guide books for the Danube on its final leg from Budapest/Hungary to the Black Sea
Having good maps when cycling the area will be important. We recommend getting yourself the "Danube Bike Trail 4" and/or "Danube Bike Trail 5" guide book (by Esterbauer). They provide maps at a scale of 1:75,000 (and 1:100,000 resp.), route instructions and hints as well as lists of accommodations and camp sites along the cycle path.
In 2016 Cicerone publishing house expanded their "The Danube Cycleway" series now covering the Danube from Budapest to the Black Sea ("The Danube Cycleway Vol. 2). Maps come at a scale of 1:150,000 which is mostly sufficient as there are simply less roads and cycle path infrastructure.