Travel by Car: The driving distance between Hamburg and Mostar following fastest route is 1800 km, within the estimated travel time of 16 hours. Recommended route goes trough Croatia, Slovenia, Austria via highway where tool fees apply. In Germany highway is free of charge.
Travel by Bus: If there are direct buses from Hamburg to Mostar, timetable and price tickets for buses can check here. Alternatively it is possible to travel via Sarajevo or Zagreb in Croatia.
Alternative ways of travelling from Mostar to Hamburg:
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 a train connection with Germany. Trains in Bosnia and Herzegovina, and Croatia are very slow, so in total travel time by train will be more than 30 hours. More information for travelling by train in Bosnia and Herzegovina you can check here.
Travel by plane: There is no direct flight, but there is option to fly from Hamburg to Sarajevo or Split.
Map with buses from Mostar: