Rab Island can be reached by ferry from the mainland Stinice ferry terminal near Jablanac which is just 5 minutes off the main E65 coast road. This car ferry runs every 60 or 90 minutes throughout the day.
The ferry docks at Misnjak at the south end of Rab island. Check the time table on this link: Rapska Plovidba.
A foot passenger only service runs from Rijeka to Rab departing daily at 17.00 in the summer months and 15.00 out of season. (Jadrolinija line 9309). The crossing takes one hour 45 minutes.
There is also a car ferry service form Valbrska on Krk island to Lopar on Rab. Krk is connected by a bridge to the mainland. The ferry form Krk sails four times a day in the summer and it is an 80 minute crossing. The service is provided by Jadrolinija line 338. Rab is also linked to Pag island by a ferry from Tovarnele near Lun at the northernmost tip of Pag island. This service is provided by Rapska Plovida and runs three time a day most days of the week (check timetables) and is a 20 minute crossing.