Travel by Car: The driving distance between Bonn (Germany) and Mostar following fastest route is 1.560 km, and travelling time is around 14 hours and 15 minutes. Recommended route goes via highway in Croatia, Slovenia and Austria where tool fees apply. The route also goes via highway in Germany, but it is free of charge.
Alternative ways of travelling from Bonn to Mostar:
Travel by train: From Mostar there is a train to Sarajevo, which have several international connection e.g. to Zagreb in Croatia. From Zagreb there is an international train to Germany. Travelling time by train is much longer compared to travelling by bus or car.
Travel by plane: There is no direct flight, but there is option to fly from Split to Cologne in Germany. Low cost company Germanwings have whole year flights from Cologne to Split.
Map with buses from Mostar: