Renting out your property in Spain
You can rent out your property in Spain for short-term lettings if you are not in your second home in Spain yourself. The tax on income from lettings is 25%. Spanish law provides tenants of long-term lettings (longer than 12 months) a lot of rights. Be aware of this when you rent out your property in Spain for short-term lettings. Always put it in writing; an inventory list will also serve as proof of holiday letting.
Renting company in Spain
You can ask a rental company to take care of this for you. There are a lot of rental companies in Spain, especially in the tourist areas. Ask for a quotation from several property companies and compare costs and occupancy rates, because they costs may vary.