To travel from Porec to Split by bus you have to do the following. First take a bus from Porec to Rijeka (Timetable here), from Rijeka you then take another bus to Split. The total travel time, for the 530 km should be around 10 hours. By car: If you stick to the speed limits you should you should be able to do the trip in 5.5 hours. From Porec it is possible to do one way car rental (fee might apply), you can see car rental offers here By train: not possible By plan: not possible