Travel by Car: The driving distance between Stuttgart and Mostar following shortest route is 1.215 km, and travelling time is around 11hours and 45 minutes. Recommended route goes via highway in Croatia, Slovenia and Austria where tool fees apply. The route also goes via highway in Germany (highway free of charge).
Travel by Bus: If there are direct buses from Stuttgart to Mostar, timetable and price tickets for buses you can check here. Alternatively it is possible to travel via Sarajevo or Split in Croatia.
Alternative ways of travelling from Stuttgart to Mostar:
Travel by train: From Mostar there is a possibility to travel by train to Zagreb (via Sarajevo), and then continue with international train to Stuttgart. Travelling by train in Bosnia and Herzegovina and Croatia is relatively slow, so travelling time in total is much longer compared to travel by bus or car.
Travel by plane: There is no direct flight, but there is option to fly from Split in Croatia.
Map with buses from Mostar: