What you are being asked
Somewhere in a Korean payment a screen will offer the amount in won or in your own currency. The industry name is dynamic currency conversion. The terminal has recognised a card issued abroad and offers to complete the payment in your currency, at a rate it shows you. The offer is a separate currency-conversion service. A provider the merchant or machine operator has contracted does the conversion at a rate it sets and shares the margin with them, and your bank receives the converted amount. Your own card’s international-transaction fees may still apply.
How to compare the cost
Check the amount in won, the offered amount in your home currency, the exchange rate and any extra fee. Compare that offer with your own card’s conversion and overseas-payment charges. Those charges vary by issuer and card; there is no single percentage that applies to every visitor.
The rules on your side
You are not obliged to accept, and the screen is not allowed to decide for you. Visa's rules require both amounts, the rate and the fees on screen, state that providers "must not choose on your behalf" or use font size or colour to steer you, and say that if the details are not visible or you feel pressured you should decline and tell your bank. Declining the conversion does not itself prevent payment or withdrawal; ordinary card authorisation still applies. Mastercard's rules run in parallel: the choice before PIN entry, no conversion as the default, both currencies and the markup on screen and receipt, refunds in the original currency.
Where you will meet it in Korea
- Cash machines. A Global ATM often puts the offer on the last screen
before paying out. Decline and take won — “Which ATMs take my foreign card?”.
- Hotel bills. Check the currency on the hotel bill before approving payment. Ask for won if you do not want the hotel’s conversion.
- Duty-free and airport shops may offer the conversion when processing an overseas card.
- Department stores and tourist-district shops may also offer a choice of currency.
- Online. Some Korean sites offer a currency selector at checkout. Pick
won.
Neighbourhood restaurants and convenience stores generally will not offer it at all.
Check the currency before approving payment
- Read the screen. Two amounts, one in your currency, means you are being
offered the conversion.
- Choose won — the screen may label it "KRW", "Local currency",
"원화(KRW)", or the amount beside the Korean flag.
- If you are handed a terminal that has already chosen, hand it back and ask
for won.
- Check the receipt before you leave. If it shows an amount in your own
currency, have it cancelled there and then and re-run in won. Ask the merchant to explain the correction and retain both receipts.
- If your bank offers a permanent block on home-currency transactions, turn
it on before you fly. Availability depends on your issuer.
Not the same question
Choosing won does not remove your own bank's foreign-transaction fee — a separate charge to check when choosing which card to bring. What choosing won removes is the *extra* layer added in Korea before your bank sees anything. The actual comparison depends on both cards’ fees and the conversion rate offered.
