Jabrin lies about 45 kilometres southwest of Nizwa. The road from Nizwa to Jabrin is good, surfaced, and well signposted; by car the journey takes around 40 minutes. From Muscat, allow about two and a half hours.
Public transport is limited. Buses from Muscat and Salalah pass through Nizwa, but there is no direct public service to Jabrin. From Nizwa, a shared taxi or rental car covers the remaining distance; taxis from Nizwa to the fort and back (with waiting time) can be arranged for a reasonable fixed fare. Hitchhiking is also common in the Oman interior and usually effective.
A rental car from Muscat is by far the most convenient approach, particularly if you plan to visit Bahla and other sites in the Interior on the same day. The road between Nizwa and Jabrin passes through the village of Bahla, whose own UNESCO-listed fort is worth a stop.