Generally, you should take at least two credit cards. Carry your primary one with you and store your back-up in a safe location.
Use your credit card, not your debit card or cash, as your 1st choice for your main purchases such as lodging, meals, transportation, retail purchases, etc.
The benefits of using your credit card include
Being able to dispute a charge, for valid reasons, after you arrive home
Not having to carry large amounts of cash
The foreign exchange rate will usually be best for a credit card vs exchanging cash at a currency exchange kiosk
Use a credit card with no foreign transaction fees - many banks offer them
Do NOT use your credit card to obtain cash from an ATM - this is considered a cash advance and the applicable fees (cash advance fee and interest charged from time of withdrawal) can be high
Do NOT allow the merchant to process the credit card transaction in USD (US dollars). Always pay in the local currency (i.e. Euros) when settling a purchase at a restaurant, retail store or wherever.
Background - many times, the restaurant/retail shop will ask you “do you want to pay in USD or the local currency (i.e. Euros)”. Since your restaurant charge is in the local currency when the bill is presented, somebody (the merchant or your credit card company) has to convert that charge into USD. The merchant will always use a higher conversion fee than your bank does. Visa and Mastercard require the merchant to ask you before putting the credit card transaction in USD. To know more about this, research Dynamic Currency Conversion (DCC).
Many foreign countries use credit cards with Chip and PIN technology. After the credit card is put into a machine for processing, the cardholder must input a PIN to approve the transaction. In the USA, we have credit cards with Chip and Sign technology. After putting the credit card into a machine for processing, a receipt is printed and must be signed by the cardholder for approval. Most foreign merchants know this about American credit cards so it’s hardly ever a problem. Because USA credit cards do not use a PIN, they will not work in most foreign credit card kiosks (e.g. at a gas station or train station).
Generally, you should take just one debit card. In fact, most people only have one. Since you are traveling with only one, make sure to secure it at all times.
Your debit card should have chip technology and your PIN should be 4 digits (many foreign ATMs work only with 4 digit PINs. Make sure to know your PIN # and not the letters. Many foreign ATMs do not have letters on the keys.
Many foreign ATMs have withdrawal limits that might be less than the daily limit you have with your bank. In that case, you can usually process one withdrawal and then put your card back in the ATM and process another withdrawal. The only issue is that you pay for 2 ATM withdrawal fees.
Before departing on your trip, check to see if your bank partners with any foreign banks and will not charge you an ATM fee when withdrawing cash.
Use cash to pay for small purchases such as taxi charges, small retail purchases, etc.
Before departing on your trip, find out what currency is used in the country you are traveling to. In many countries, USD are widely accepted so there is no need to obtain that country’s currency.
For instance, Cambodia has their own currency but USD are widely accepted. You can either bring USD with you or many ATMs will issue USD in addition to the Cambodian Riel.
Exchanging USD for the local currency is generally a more costly process than obtaining cash at an ATM with your debit card
What’s your liability if your card is lost or stolen?
Did you know that federal law limits your liability for unauthorized charges if your credit or debit card is lost or stolen? Do you know which card can be more costly to lose? Read the Federal Trade Commission webpage about it.