Travel by car: the driving distance between Karlsruhe in Germany and Banja Luka is about 9 hours and 45 minutes following the shortest route passing through Austria, Slovenia and Croatia; on this route tolls do not apply only in Germany. There is also an option to travel through Switzerland and Italy; this route is a little bit longer and toll fees apply all the way.
Travel by bus: if there are direct buses between Karlsruhe and Banja Luka, the schedule and ticket prices can be found here. It is possible to travel across Zagreb and Munich, but there is also an option to travel via Budapest which is a bit longer.
Alternative ways of travelling between Karlsruhe and Banja Luka:
Travel by train: on this route it is possible to travel by train; there are two options: the route across Zagreb and Munich or across Budapest in Hungary. The second trip is longer. More on trains in Bosnia can be found here.
Travel by plane: there are no direct flights on this route; it is possible to travel by train to Zurich and then take a direct flight to Banja Luka.
Map with buses from Banja Luka:
Prikaži Bus Banja Luka na većoj karti