Holidaymakers outside an expanded EU will be affected
Nationwide will pass on a fee to customers who use its credit and debit cards abroad in a change of policy.
From 6 May, customers with a Nationwide credit card will be charged 0.84% for every foreign transaction outside continental Europe.
The same fee will apply to debit card transactions from 1 June, and both fees will be increased to 1% from July in line with a rise being imposed by Visa.
Nationwide stresses that it is still not charging commission.
The building society was one of the few card providers not to levy extra charges for the use of cards overseas.
A Nationwide spokeswoman said that it was sending information to credit and debit card holders affected by these changes.
People using cash machines or going into shops in countries such as the US will be charged the fee, but they will still not be charged commission by Nationwide. That is around 40% of Nationwide customers' overseas card use.
However, travellers using cards in EU countries as well as Iceland, Israel, Turkey, Switzerland, the Channel Islands and some former French colonies will not be charged. Some Nationwide customers who have a Mastercard, rather than Visa, will also be unaffected.
"As a prudent organisation, we have to maintain the balance between offering competitive products whilst ensuring these are sustainable in the long term, particularly in the current economic climate," the Nationwide spokeswoman said.
"By passing on the fee of 0.84% that Visa currently charge us, we can continue to offer a number of benefits."
She said Nationwide previously absorbed the fee.
Nationwide cards are generally still regarded in "best buy" tables as very competitive for those using their cards abroad.