The calculated distance (air line) between Castelló de la Plana and Peníscola is approximately 35 miles respectively 57 kilometers.
By car or train, the actual journey to Peníscola is certainly longer, as only the direct route (as the crow flies) between Castelló de la Plana and Peníscola has been calculated here.
Air line (approximately)
57 kilometers
31 nautical miles