The currency in Costa Brava, as in the rest of Spain, is the Euro.
The vast majority of restaurants, hotels and shops will take the usual credit cards such as Visa and MasterCard, but if you’re venturing a little further afield or need a quick snack, it’s best to have some cash in your pocket. Smaller shops, stores and kiosks may not take credit cards.
ATMs are plentiful, but be aware that you may be charged a fee to take out cash. Tipping is appreciated but not compulsory.