Research the fees for all your debit and credit cards before you leave the United States; the cards with the lowest international transaction fees are the cards you will use when traveling in Great Britain. Using debit cards is usually the best way to avoid currency exchange fees, and are always far less expensive than changing your U.S.-denominated cash or traveler's checks to GBP at an airport currency exchange counter.
Consider opening a new checking or credit card account at a bank or credit union if your current providers do not offer free or competitive rates. Bankrate.com is a good source for up-to-date information on which credit card companies and banks offer the best rates. As of their last survey (in 2009) two major banks offer free-of-charge currency conversion when you use their debit cards in overseas ATMs: Capital One and TD Bank. Both offer free currency exchange when you use your debit card either at the point of sale or through the ATM.
Call your credit union, if you have one, to check their fees before you travel. If you do not belong to a credit union, consider joining one if you are eligible. Credit Unions generally offer the lowest fees for debit card usage, and their currency exchange fee is usually no more than 1 percent.
Question the bank or credit union associated with the card(s) you choose, and ask them detailed questions--not only about currency exchange rates and fees, but also about any other charges for using out-of-network ATMs.
Sign up for online banking at the institution that issued the debit card(s) you plan to use, so that you can track your expenses and any associated fees when you get to Great Britain.
When you arrive in the U.K., use your debit card at an ATM located in a bank rather than a freestanding commercial ATM, preferably one that shares a network with your home institution. Withdraw your cash in GBP, and as soon as you can, log onto your checking account online to make sure you are not being charged for unexpected fees.
