Travel by car: the driving distance from Liege in Belgium and Mostar is 1700 km which equals a travelling time of approximately 15 hours and 30 minutes under normal circumstances. The recommended route goes through Germany where highway is free of charge while in Austria, Slovenia and Croatia toll fees apply.
Alternative ways of travelling between Liege and Mostar:
Travel by train: it is possible to travel by train on this route. There are two options: it is possible to travel through Germany, Austria and Hungary or through Germany, Czech Republic and Hungary. Trains in Bosnia and Herzegovina, and Croatia are very slow, so in total travel time by train will be much more compared to travelling with bus. More information for travelling by train in Bosnia and Herzegovina you can check here.
Travel by plane: there are no direct flights on this route.
Map with buses from Mostar: