Rab is reached by ferry. There is no bridge and no airport.
The main connection is from Jablanac on the mainland to Mišnjak on the southern tip of the island — a crossing of about fifteen minutes. Jablanac is on the coastal highway (the Magistrala, D8) between Senj and Starigrad. Jadrolinija runs this route frequently throughout the day in summer; the ferry takes cars, motorbikes, and foot passengers.
A second route connects Valbiska on the island of Krk to Lopar at the northern end of Rab. This crossing takes around 45 minutes and is useful if you are island-hopping from Krk. Rapska Plovidba operates this line.
From Split or Rijeka there are seasonal catamaran services to Rab town itself — fast (around two hours from Rijeka) and foot-passengers only.
If you are travelling without a car, the easiest approach is the Jablanac–Mišnjak ferry followed by the island bus service to Rab town. In summer, buses meet the ferries.