It's important to have the currency of the country you're visiting once you arrive, especially since not all places accept credit cards. You will typically get a much better conversion rate with your local bank or currency exchange than at the airport, and you can get the cash in less than a week. Once you've arrived to your destination, if you run low on cash, use a local ATM to stock up on money as the fees are usually much lower and the conversion rate is exact. The best case scenario? If you bank with a large international entity, see if you can find an ATM for your bank.