Spanish pharmacies (farmacias), pet stores and vet clinics all sell antiparasitic products, but exactly which products can be sold without a prescription changed under Real Decreto 666/2023, which overhauled how veterinary medicines are distributed, prescribed, dispensed and used in Spain. The regulation specifically keeps a category of 'medicamentos veterinarios no sujetos a prescripción' that can be sold through retail channels including pet stores and pharmacies, but it doesn't treat every antiparasitic product the same way — classification depends on the specific product's own authorisation.
This is genuinely worth checking product by product rather than assuming either that everything needs a prescription now, or that basic flea and tick products are automatically exempt the way they might be in some other EU countries. A pharmacist or the product's own packaging and leaflet will confirm its current status, and Spain's medicines agency (AEMPS) maintains the official CIMA database where a product's classification can be looked up directly.
Anything beyond basic antiparasitics — prescription diets, antibiotics, chronic condition medication — requires a vet's prescription in Spain, the same as almost anywhere in the EU. If your pet is on regular medication from home, bring enough to cover the trip comfortably plus a few extra days, since matching an exact brand on short notice isn't guaranteed even for a common product.