Using a MasterCard abroad is about to get more expensive for many consumers.

MasterCard International Inc. says it plans to charge fees for all card transactions abroad, not just those where it converts to dollars purchases made in a foreign currency. Earlier this month, Visa USA Inc. started levying a 1% fee on every charge made outside a cardholder's country. American Express Co., meanwhile, charges a 2% fee for transactions abroad where currency conversion occurs.

MasterCard says that starting Oct. 1, it will charge issuers a fee of 0.8% on all transactions when the card holder and merchant are from different countries. The company also plans to levy an additional 0.2% whenever a merchant's foreign currency needs to be converted. The new fees apply to users of both MasterCard credit and debit cards, and include ATM withdrawals and debit-card purchases.

Previously, when someone used a MasterCard or Visa while traveling abroad, the companies added only a 1% fee for purchases that required currency conversions. The banks that issue credit cards would frequently add their own fees, resulting in total currency-conversion charges as high as 3% in some cases. But travelers previously could avoid those fees by shopping at a growing number of foreign merchants that allowed travelers to use their cards to pay in dollars. For example, a car-rental agency in Europe would figure out the cost of a rental in dollars, and charge your card that amount. Merchants, however, charge a fee for doing that.

The new MasterCard fees will be charged directly to the issuer and as a result, won't show up on credit-card bills as part of the transaction amount. If the issuers decide to pass along the fees, consumers could face fees from both the merchant and the card issuer for the same transaction if the transaction is done in dollars.

Some banks such as J.P. Morgan Chase & Co. are choosing not to pass along the new fees and plan to continue to charge consumers only for purchases where MasterCard converts the currency. However, other issuers, including MBNA Corp., HSBC Holdings PLC and Capital One Financial Corp., plan to begin charging fees for all MasterCard transactions abroad.