Yes, you'll use both at once. No, it's not a scam. Eleven questions travellers actually ask, answered from the till side.
01The system in one paragraph
US dollars and Cambodian riel circulate together at a fixed street rate of 4,000 riel per dollar. Anything over about $5 is priced and paid in dollars; your change under a dollar comes back in riel notes. There are no US coins in the country — that's what the riel is for. It looks chaotic for a day and then becomes the most sensible dual system you've used.
02What your dollars must look like
Torn, marked, heavily creased or pre-2009 bills get refused at tills that will happily take a crisp one. Bring newer-series notes, nothing above $50, and break hundreds at banks, not shops. ATMs (ABA is everywhere) dispense dollars; $5 withdrawal-fee territory, so pull larger amounts fewer times.
03Where riel rules
Markets, street food, tuk-tuk change, countryside anything. Keep a 20,000–40,000 riel float in a separate pocket and small transactions stop involving mental arithmetic entirely.
04Cards, QR and the ABA effect
Phnom Penh and Siem Reap have leapfrogged into QR payments — the local KHQR system is on every second stall, and ABA transfers are how locals pay each other. Foreign cards work in hotels and proper restaurants (3% surcharges common); the islands remain cash country.
05The ATM strategy that saves real money
Cambodian ATM fees are the region's steepest — $5–6 per withdrawal is standard, and machines cap around $250–500. The maths is blunt: five small pulls cost you a decent dinner in fees. Pull large, once per city, from ABA or ACLEDA machines (best limits, most reliable), always in dollars, always declining the machine's own conversion offer — 'continue without conversion' saves the hidden 4–7% spread every single time. Canadian and some EU cards get flagged fastest here of the three countries; a two-line message to your bank before flying beats any amount of hotel-lobby phone drama.
06Tipping, bargaining and the price of politeness
Cambodia's norms sit gently between Vietnam's no-tip default and Western expectation. Restaurants with service charge printed: nothing more needed. Street food and markets: never expected. Tuk-tuk drivers on day hire and temple guides: $2–5 rounds the day off well and is genuinely felt. Bargaining belongs in markets only — open at half, land around 60–70%, and keep it smiling; the $0.50 you're fighting for matters more on their side of the table. Hotels quote in dollars, corner shops in riel, and nobody anywhere will blink at either — that's the two-currency system working exactly as designed.
07The three money scams that actually occur
Cambodia's money tricks are low-stakes and predictable once named. One: the torn-dollar rejection cycle — vendors refuse imperfect notes yet hand them out in change; inspect every dollar you receive like they inspect yours. Two: the 'no small change' shrug that rounds your change down — carrying a brick of 1,000/2,000-riel notes deletes the move entirely. Three: ATM-lobby 'helpers' offering to speed your withdrawal; decline with a smile and let the door close. That's genuinely the list — violent or elaborate cons are rare, and treating every interaction as a scam-in-waiting costs more (in goodwill and joy) than the $2 these tricks were ever worth.
08Questions we actually get
Should I exchange money before arriving?
No — ATMs at both airports dispense dollars, and riel accumulates naturally as change.
Are prices quoted higher to foreigners?
Markets: opening prices, yes, everywhere on earth; metered PassApp rides and ticketed sights are flat-rate honest.
What do I do with leftover riel?
Spend it at the airport café or keep small notes — outside Cambodia it's souvenir paper.
Can I pay for everything by card in 2026?
In Phnom Penh and Siem Reap you could nearly card-and-QR your whole stay (3% surcharges aside) — but the islands, buses and anything rural remain firmly cash, so the answer is: no, carry both.
Founder of Mekong Atlas. Twelve years riding buses, trains and slow boats across Vietnam, Laos and Cambodia — every route on this site travelled in person, prices re-checked on the ground.