World travelers, check your credit card. You might be charged a foreign exchange conversion fee even when making purchases in U.S. dollars.

Here's an email I got from Mary E.:

For our occasional international travel, we purposely keep a Capitol One Visa credit card that charges no foreign currency conversion fee. On a recent trip in Switzerland, several times when we used the card, we were asked whether we wanted to pay in U.S. dollars or Swiss francs. We did not know which would be to our advantage. In each case, we were told by the business that it would usually be to our advantage to pay in dollars. We chose dollars, but noticed when presented with the receipt that the transaction processing entity charged a currency conversion fee that was included in the exchange rate. Would we have been better off paying in Swiss francs, since our Capitol One card charges no conversion fee?

I'm somewhat familiar with Mary's issue because of an article I wrote yesterday on credit card issuers changing terms on consumers before credit card reforms kick in February.

In my reporting, Greg McBride of Bankrate.com told me that issuers have been getting more creative with fees. One of them is foreign conversion fees.

Usually, you only trigger a fee when you are making a purchase in a foreign currency. But McBride says card issuers have started adding the fee even if you are making purchases with U.S. dollars outside the country. The Caribbean, for example, is one place where you have the option of paying in dollars or other currency.

"Now we are seeing issuers assess the fee regardless of the currency...as long as the transaction takes place on foreign soil," McBride says.

If any of you know of a card that doesn't charge a foreign coversion fee, let us know. We'll pass the word onto Mary.