We found for my daughter's stay in Barcelona this summer that our various credit cards had different rules (here I'm not referring to the question you actually asked about what currency a transaction was paid in), about whether fees were charged for overseas use. We called each company prior to her trip to determine which was best for both charging items and for ATM withdrawals. Also, we notified them in advance that charges would be appearing from specific countries so they didn't close down the credit card over suspicion that it was stolen.

Maria Newton, MA