The currency in Spain is the Euro.
When changing money, you should always use official money exchange offices or banks, as possession and use of counterfeit money is considered a very serious crime in Spain and may lead to
If you are travelling to or from a country outside the European Union you must declare any cash of over 10,000 euros or more (or the equivalent in other currencies) to HM Revenue & Customs.
Credit cards and ID
When buying goods in Spain with credit/debit cards, all al customers, regardless of nationality, must show ID. You may be able to use a driving licence or a photocopy of your passport, but you may be required to show your passport.