Best credit cards for overseas travel

Here's a simple way to save some money every time you make a purchase on your trip. Make sure you have the right credit card in your wallet—one that does not charge a foreign transaction fee.

"About 90 percent of all credit cards have a foreign transaction fee, which can be as high as 3 percent," said Odysseas Papadimitriou, CEO of CardHub. "Three percent might not sound like much, but when you multiply it by the typical budget of an international trip, it can add up to a lot of money."

Does your card have this fee?

If you're not sure, check the terms and conditions. A few big-name credit card issuers have started to eliminate this fee on some of their cards.

Chase now has 13 cards that don't have a foreign transaction fee, including the Marriott Rewards Premier credit card, Southwest Airlines Rapid Rewards Premier card, United MileagePlus Club Visa and British Airways Visa Signature card.

"Most of these cards are designed for frequent travelers and have benefits that would suit their specific needs and wants," said Paul Hartwick, a spokesman for Chase. "Features like bonus points for travel purchases and no foreign transaction fees are especially attractive to these customers."

American Express recently dropped the fee for its Gold, Platinum and Reserve Delta SkyMiles credit cards.

"If your card has this fee, you might want to apply for another one before your trip," said Bill Hardekopf, CEO of LowCards.com. "There are a number of really good cards available that you might want to consider."

For example, consider the Chase Sapphire Preferred card, BankAmericard Travel Rewards card and the Barclaycard Arrival Plus World Elite MasterCard.

A few card issuers—Capital One, Discover and Pentagon Federal Credit Union—do not have foreign transaction fees on any of their cards. The Capital One Quicksilver and Venture Rewards cards come highly recommended by various comparison websites. (See a full list of recommended cards at CardHub.)

What about a smart card?

Unless you frequently travel outside the country, you probably have a credit card with a magnetic strip on the back. That could be a problem in other parts of the world where they've converted to EMV technology—the so-called "smart card" that uses an embedded microchip to verify your identity.

"It's a good idea to have the EMV card, but it's probably not as important as some people would have you believe," said Ed Perkins, who writes for SmarterTravel.com. "I wouldn't stay home because you don't have one." (Read More Whether PIN or signature, smart cards are coming)

America is in the process of switching to EMV cards, but there's no need to wait. See if your bank can give you a new chip-based card. Chase, Citi and Bank of America now offer a number of cards that are EMV compatible—they have both a mag strip and a chip. And as an added bonus, they don't have a foreign transaction fee. (See a list of EMV-enabled credit cards on LowCards and NerdWallet.)

Getting cash in another country

You may be tempted to get some foreign currency at the airport. Travel experts advise against that because the exchange rate is so bad. Wait until you get to your destination and find an ATM.

The average charge for currency conversion is 6.73 percent higher at a bank, and 10.17 percent higher at a Travelex location, than using a credit card with no foreign transaction fee, according to CardHub's 2014 Currency Exchange Study.

But watch out for other fees. The average foreign ATM fee is around $2.78 per transaction. You may be able to avoid that if you use a cash machine that's affiliated with your bank. (Read More Be on alert! Vacation rental scams an 'epidemic' )

Bank of America has a no-fee agreement with banks in many countries, including Australia, Canada, China, England, France, Germany, Italy and Mexico through its Global ATM Alliance, which will save you $5 per transaction. Keep in mind, there still may be a foreign transaction fee of three percent.

A few checking accounts now offer debit cards that don't have a foreign transaction fee, so you can withdraw cash from any ATM without getting dinged.

Before you leave

No matter where you go or what card you have, contact your bank or card issuer and let them know about your travel plans. Otherwise, you run the risk that their fraud prevention computer programs might see these out-of-profile transactions, suspect a problem and shut down the card.

It's also a good idea to make sure you've paid off the balance, so you don't run out of credit while you are away.

Check with your bank to find out what sort of charges you might incur if you use their card when you're away and find out what, if anything, you can do to avoid those fees. (Read More Fight fraud with remote control for credit cards )

One more money-saving tip: Never let a merchant convert your purchase into U.S. dollars. That may seem convenient, but you'll get a lousy exchange rate and still have to pay a conversion fee when that transaction is processed by your credit card company.

"Pay in the local currency and let your card company take care of the conversion for you," advised Charles Leocha, chairman and co-founder ofTravelers United. "You'll get the best exchange rate that way."

—By CNBC contributor Herb Weisbaum. Follow him on Facebookand Twitter @TheConsumerman or visit The ConsumerMan website.