My pick
My tip“Closed Sunday; pick-up is mostly digital, so ask for a practical demonstration of running the battery and fridge, and video any previous damage to avoid deposit claims.”
A leading German camper rental company with modern vans (Volkswagen California, Ford Nugget). It has stations in Spain in Madrid, Barcelona, Málaga, Valencia, Bilbao and Sevilla, with one-way trips possible and unlimited kilometres on many deals.
Address
C. Mir 10, Vicálvaro