Bulla Regia is near the town of Jendouba in northwestern Tunisia, about 10 km north on the road toward Ain Draham. From Tunis, the drive takes about two hours via the A3 motorway to Bou Salem, then northwest toward Jendouba. Shared louages (taxis) run from Tunis to Jendouba, from where you can take a local taxi to the site.
The most efficient way to visit is to combine Bulla Regia with Dougga, the spectacular hilltop Roman city about 30 km to the south. The two sites make a full and rewarding day trip from Tunis or from a base in Béja. There is a small site museum at the entrance to Bulla Regia and a café. Tickets are inexpensive and include access to all the underground houses. The site keeps standard Tunisian heritage site hours — confirm current times before visiting, as they shift seasonally.