If you are coming to Rab with a vehicle than you have to know that island Rab is connected to mainland with ferry line Stinica - Mišnjak. It is a short ferry ride of approximately 15 minutes. You can find timetable at www.rapska-plovidba.hr. During holiday season there can be more lines than defined in timetable.
You can arrive by catamaran from Rijeka or Novalja. There is a line once a day from each city. You can get more information on www.jadrolinija.hr.
Nearest airports are Rijeka and Zadar.