Cash!
Greece, unlike other European countries, is a cash-based economy, therefore bring plenty of cash. If not, ATMs can be found, especially in the heart of major cities; but, on lesser-known islands, where many restaurants and establishments do not accept credit cards, this may be a problem.
Don't worry; credit cards are accepted in the majority of bigger stores (shopping stores, large supermarkets, malls, restaurants in busy locations). However, try to always have cash on hand; if in doubt, always inquire before proceeding to the register.
Many Greek banks have ATMs located outside the bank in glass-enclosed chambers. In Greece, getting cash through ATMs is more popular than any other method of money exchange, and it normally costs €2-3. Although a few hotels, restaurants, and tavernas may have one, street-side ATMs are still the most prevalent. This is one of the top Things about Greece You Should Know before traveling to this country.