Bouillon has no railway station. By car, it is best reached from Liège (110km) or Luxembourg City (70km) via the E411 motorway to Neufchâteau and then south on smaller roads. From Brussels allow about two hours. The roads into the Semois valley are scenic but winding.
By bus, TEC operates services from Libramont railway station (35km north on the Brussels–Luxembourg line) into Bouillon, but services are infrequent. Most visitors arrive by car.
Cycle touring is a serious option: the Semois valley is well established on the Belgian cycling map and several long-distance routes pass through Bouillon, including the RAVeL network of traffic-free paths.