Where a card works, and where it does not
Card acceptance in Mexico splits cleanly along the line between registered businesses and cash businesses, and the split is more predictable than it looks. Supermarkets, chain pharmacies, department stores, hotels, sit-down restaurants, museums, intercity buses and ride-hailing apps take cards, including contactless. Markets, street food stalls, neighbourhood fondas, small bakeries, tortillerías, laundries, parking, tips and most street taxis do not, or take them unreliably.
The practical consequence is that you cannot run a Mexican trip on a card alone without eliminating most of what makes eating in Mexico worthwhile. Plan on a working float of cash refreshed every few days rather than one large withdrawal at the start.
Bank ATMs cost less than the machines you keep walking past
CONDUSEF, the financial consumer protection agency, states plainly that the commission a bank charges for the use of its ATMs depends heavily on where the machine is installed, and that machines in supermarkets, shopping centres, airports, bus terminals, convenience stores, pharmacies and petrol stations generally charge more than those installed in bank branches. Its recommendation is to prefer branch machines.
That maps directly onto a visitor's day. The machine in the airport arrivals hall, the one inside the convenience store on the corner and the free-standing unit in a tourist street are the expensive end of the range. A branch of a major bank, ideally inside the branch during opening hours, is the cheap end and also the better-lit and better-monitored end.
The fee has to be on the screen, so read it
Mexican ATMs are required to display the commission before you complete the transaction, and CONDUSEF frames this as a consumer right: when you use a machine belonging to a bank other than your own, the commissions must be shown on screen so that the user decides whether to accept and continue. That screen is your cancel point. If the number is higher than you expected, cancel and walk to a branch machine.
Two other costs sit outside that screen and neither is Mexican. Your own bank at home usually charges a foreign-withdrawal fee and a foreign-exchange margin, and both are set by your card issuer, not by the Mexican machine. Fewer, larger withdrawals reduce the fixed portion of that, which is the real argument for taking out more per visit rather than topping up daily.
Always decline conversion into your own currency
When a Mexican ATM or card terminal offers to bill you in your home currency instead of pesos, the correct answer is always no. The offer, known in the industry as dynamic currency conversion, means the machine's own provider sets the exchange rate and adds its own margin, then bills your bank in your home currency so your bank has nothing left to convert. You lose the ability to compare, because the conversion has already happened before your card issuer sees it.
Choosing "charge in MXN" or "continue without conversion" hands the conversion back to your card network, which applies its own published rate. The screen wording varies by machine and is often designed to make the home-currency option look like the safe, familiar choice. It is not.
Small notes are a daily problem, and counterfeits are a smaller one
Mexican ATMs often pay out in large denominations, and a 500 peso note is close to useless at a taco stand, a market stall or a short taxi ride. Break large notes deliberately at supermarkets, chain pharmacies and larger restaurants where a till has change, and keep 20s, 50s and 100s aside for the places that need them. A small vendor who genuinely cannot break a big note is a practical problem you solve in advance, not an argument to have at 9pm.
On authenticity, Banco de México's guidance is a three-step habit rather than a gadget: touch, look and turn the note. Touch for the raised printing and the feel of the paper or polymer, look through it against the light for the watermark, security thread and see-through register, and tilt it to see the colour-shifting element and multicoloured denomination move. The same document notes that marker-pen tests are not reliable, and that several note families, F, F1 and G, are legitimately in circulation at once, so two genuine notes of the same value can look quite different.
Card skimming and where you physically use your card
Skimming risk in Mexico is concentrated at unattended machines rather than at restaurant tables. CONDUSEF's ATM advice is concrete: check that nothing foreign has been fitted over the card slot, cover the keypad with your hand when entering your PIN, avoid machines in dark or empty places, especially at night, and keep the receipt so you can match it against your statement and spot an anomaly early.
CoDi, DiMo and SPEI: what locals use and you cannot
The everyday Mexican alternative to cash is not a card, it is an instant bank transfer, and it is closed to visitors by design. Banco de México operates SPEI for interbank transfers, and its public guidance states that to send one you need an account at a participating financial institution plus the recipient's 18-digit CLABE, card number or, through DiMo, the 10-digit mobile number linked to their account. CoDi sits on top of the same rails, using QR codes and NFC to trigger a transfer, and Banco de México states it carries no additional commissions, which is exactly why small businesses like it.
All of it requires a Mexican account. A visitor asked to "pay by transfer" or shown a CoDi QR code should say they do not have a Mexican account and offer cash or card. It is a normal conversation, not an awkward one, and it explains why some small operators quote you a slightly different price for cash.
Setting yourself up before you land
Tell your card issuer you are travelling, check what it charges for a foreign ATM withdrawal and whether it refunds any of it, and carry two cards from different networks kept in different places. Install a currency converter you can read at a glance so the decision at a payment screen takes two seconds. On arrival, withdraw once at a bank branch machine rather than in the terminal if you can wait, and start breaking notes early.
This guide covers paying as a visitor. It does not cover opening a Mexican bank account, exchange-house rates, tax refunds on purchases, or the tipping conventions that determine how much of that small-note cash you will actually need.