For the time being, there is no motorway to Dubrovnik. Considering how narrow non-motorway roads are, you’re safest sticking with the motorway as far as Split. Do be aware that during weekends approaching August, all roads become catastrophically busy, especially at borders, motorway toll booths and tunnels. Avoid weekends! To approach Dubrovnik, you can either travel:
Via Split: From Split, follow signs for Dubrovnik leading you inland. (Avoid the coast road passing through Omiš, a terrible bottleneck). Just south of Metković you pass through a corridor belonging to Bosnia and Herzegovina, so keep your passport or ID card handy.
Via Bosnia and Herzegovina: You can enter “BiH” from the A3 (E70) heading east from Zagreb, or one of the roads heading south from Hungary. Of the possible routes, Bosanska Gradiška – Banja Luka – Jajce – Mostar is probably quickest, but you may wish to take a detour through the fair city of Sarajevo. When you get into Dubrovnik, a one way system leads east and west of the Old Town – try to have a map handy! Check out the Croatian Automobile Club website at www.hak.hr for traffic information.