A trip abroad has an invisible line item: the cost of paying for things. Between card fees, marked-up exchange rates and a checkout trick designed to confuse you, spending money overseas can cost several percent more than it should. Here's how to keep that money in your pocket.

Foreign transaction fees

The most common charge is the foreign transaction fee — a surcharge many banks and card issuers add every time you buy something in another currency, as the CFPB explains. It's typically around 1% to 3% of each purchase, and it applies to card spending processed abroad. On a $3,000 trip, a 3% fee is $90 for doing nothing but paying.

The fix: carry a card with no foreign transaction fees. Many travel-focused credit cards (and some checking accounts and debit cards) waive them entirely. Check yours before you go; if it charges, it may be worth opening one that doesn't.

Dynamic currency conversion — the trap to decline

Here's the sneakiest one. When you pay by card overseas, the terminal or ATM may ask whether you'd like to be charged in your home currency instead of the local one. It sounds helpful. It usually isn't.

This is dynamic currency conversion (DCC) — the merchant's payment processor converts the price into your currency on the spot, almost always at a worse exchange rate than your card network would use, and sometimes with an added markup, as Investopedia describes. You've simply handed the conversion to whoever profits from a bad rate.

The fix: whenever a card machine or ATM offers to charge you in your home currency, decline and choose the local currency. Let your own card network do the conversion — its rate is typically far closer to the true market rate.

Cash, ATMs and airport kiosks

For cash, the rules are similar:

  • Airport and hotel currency kiosks offer convenience at a steep price — wide margins between their buy and sell rates. Avoid changing large amounts there.
  • ATMs usually give a better rate than a currency booth, but watch for two charges: your own bank's out-of-network/international ATM fee, and the local operator's fee. Withdraw larger amounts less often to spread fixed fees, use in-network or partner ATMs where possible, and — again — decline DCC at the machine.
  • Be wary of standalone ATMs in tourist areas, which often carry the highest fees and push DCC hardest.

A simple pre-trip checklist

  • Get a no-foreign-transaction-fee card and make it your main spender abroad.
  • Always pay in the local currency — decline "charge in your home currency."
  • Use bank ATMs for cash, in larger, less frequent withdrawals.
  • Skip airport/hotel exchange counters for anything but a small emergency float.
  • Tell your bank you're traveling so payments aren't blocked, and carry a backup card.

The bottom line: the fees that pile up abroad are avoidable, and mostly come down to two habits — using the right card and always choosing the local currency. Boursel gives no individual financial advice; the takeaway is that a few minutes of prep can save you the equivalent of a nice dinner out — or several.