Hotels in Buda Castle are located in the protected, so called, traffic calming zone. Driving into the protected zone is possible with entry permits only, however one can stay in the zone up to 30 minutes (e.g. short visits, pick-ups) without getting fined. (Over 30 minutes stay, surcharge has to be paid at the exit.)
Hotels normally offer ad-hoc parking permits (more one day parking card) for their guests based on individual assessment only. It is strongly recommended to contact the Hotels’ receptions about the entry and parking options before getting into Buda Castle.