Getting to Plitvice Lakes from Dubrovnik
The most comfortable (and the most expensive way) to reach Plitvice National Park from Dubrovnik is to fly to Zagreb and take a bus to Plitvice. For this option the total journey time, including airport transfers and check in procedure is at least 7 hrs.
Taking a direct bus from Dubrovnik to Plitvice is another option – there is a direct bus from Dubrovnik to Plitvice that leaves everyday at 18:00 arriving there at 3:35 am (total journey time 9.35 hrs). However, I would not recommend you to take this bus as arriving at Plitvice in the middle of the night is not convenient at all.
My recommendation is a bus ride from Dubrovnik to either Split, Šibenik or Zadar and change there for another bus to Plitvička Jezera (Plitvice). This journey can take up to 12 hrs, depending of bus timetables. From Zadar it takes about 2 hours, and from Split just less than 6 hrs to reach Plitvice.
If you choose this option, I would advise you to take the first, early morning bus from Dubrovnik to Split,Sibenik or Zadar to be able to arrive at Plitvice at reasonable time, before dusk. According to current timetables, if you take the 6am bus from Dubrovnik, change in Zadar you will be at Plitvice around 4.30pm. If you take the 7am bus from Dubrovnik, change in Split you will be at Plitvice around 6pm.
The most comfortable option is probably to travel to Split, Šibenik or Zadar and stay the night there (include some sightseeing) and then head to Plitvice following morning. If you choose this option, I would also suggest you to consider visiting Krka National Park, in close vicinity of Šibenik, which has beautiful lake, island, monastery and waterfalls.
If your time is scarce and you don’t want to spend most of the day travelling, you can also consider taking any evening bus to Zadar (lets say 5pm one), overnight in Zadar and take morning bus to Plitvice where you can arrive well before midday.
While choosing your buses, bear in mind that all buses travelling from Split to Zagreb via Lika stop at Plitvice national park entrance. Buses that travel via new highway do not stop at Plitvice.
More relevant reading, maps, directions and info: