New research by Which? reveals some banks charge exorbitant fees for overseas transactions with details often hidden away on providers' websites or undisclosed on statements.
Which? compared the amount charged by the country's seven biggest banks and building societies* for the same €5.95 (£4.94) debit card purchase and a €20 ATM withdrawal.
Norwich and Peterborough's (N&P) Gold Light current account came out on top. Account holders aren't charged any fees for overseas use.
In comparison, Halifax charged 33 per cent more than N&P. Halifax's fees also charged 29 per cent more than both HSBC and Barclays. Lloyds TSB charged 15 per cent more than N&P for the ATM withdrawal.
Additional fees can make card purchases incredibly expensive. For example, 10 transactions of £50 made with a Halifax debit card would cost the cardholder £28.75. The same 10 transactions made with N&P would be free.
Which? also found it difficult to calculate how the foreign loading fees had been calculated using the bank statements alone.
HSBC, Halifax and Lloyds TSB included their foreign loading fee as part of the exchange rate. Santander showed only the exchange rate with no mention of the foreign loading fee, even though it had charged one.