Some CC companies charge you a 3% fee even if you charge the puchase in U.S. dollars. According to bankrate.com, B of A, Citibank, Wells Fargo, Wachovia, among others, do this. Amex and Chase do not. Of course, the best deal is to pay the hotel bill in local currency but that's not always convenient. Some hotels, like Langham International, have the amount in both local currency and U.S. dollars on the charge slip so you can indicate your preference. In that case, you can do a quick calculation to see which is more advantageous for your situation.