If you are travelling from Split to Dubrovnik one of the best options is to take a high-speed catamaran. KRILO is one of the shipping companies operating catamarans on this route (daily, from mid-April until end of October).
By taking this catamaran, you can easily go island hopping and visit the islands of Brac, Hvar, Korcula and Mljet as well as the city of Makarska on the land.
For those who like to travel on their own pace, renting a car and driving between Split and Dubrovnik would be a great choice. This way you have flexibility and stop along the way to have a dip into the crystal clear sea or have a stop for a lunch. Be sure to book your car rental well in-advance to get affordable deals!
The fall is great time for exploring natural wonders of Plitvice Lakes; the best way to do this is to take your private tour from Split (round-trip transfer + great local guide!). You'll love it!
Catamarans sailing on this route are super-fast and air-conditioned, with all facilities needed for a comfortable journey. They carry only passengers and can hold up to 400 persons.
KRILO offers two catamaran routes, both running from Split to Dubrovnik and vice versa with stops on the islands along the way (Milna on Brac) - Korcula - Pomena on Mljet). Sailing time between Split and Dubrovnik is around 4 hours 30 minutes.