From Osijek it is possible to Travel to Lucerne, via Zagreb. First you have to take a domestic bus line from Osijek to Zagreb, these buses, which are quite frequent, departures from the main bus station in Osijek. Once arrived in Zagreb, you can take the daily bus to Lucerne, timetable for that bus you can see below. The total travel time for the 1130 km long bus route from Osijek to Lucerne is about 14-15 hours. Return tickets for both route has a discount so if you plan to travel back you should buy one.