Credit cards can be used in most restaurants and stores in tourist locations, as well as ATMs (cajeros). Visa and Mastercard are the two most popular cards, which are widely accepted throughout Argentina. American Express is more of a third option. Do not forget to have your passport on hand for identification purposes when a purchase with a credit card is made. Check with the credit card company before traveling to make sure it will work abroad. It is also prudent to carry sufficient pesos in small towns in the event credit cards are not accepted.