Changing money in Thailand without being skinned.

What you are actually paying: the spread

Thai exchange counters mostly advertise no commission, and mostly that is true. The money is made in the spread, the gap between the rate at which the counter buys your currency and the rate at which it sells it, both measured against the interbank rate that banks trade with each other. A counter quoting a buy rate a whisker below interbank is taking a fraction of a per cent. A counter quoting one two or three per cent below is taking two or three per cent, and it is doing so in plain sight on a lit board that you are entitled to read before you hand anything over. There is no hidden fee to hunt for. The rate is the fee.

This makes comparison easy, which is why Thailand is a good country in which to change money and a bad country in which to be lazy about it. Look up the interbank rate for your currency before you leave the hotel, note the number, and compare every board you pass against it. The difference between the best and worst legitimate counters within a few hundred metres of each other in central Bangkok can be several per cent, and the difference between the best city counter and the airport can be more again. Two minutes of attention is worth more per hour than most things you will do that day.

Why the airport is the worst rate in the country

Airport counters serve a captive customer at the least price sensitive moment of the trip, and they pay airport rents to do it. Both facts land in the spread. The counters in the arrivals concourse at Suvarnabhumi and Don Mueang, and the equivalents at Phuket and Chiang Mai, are consistently among the widest spreads you will encounter in Thailand, and the ones inside the secure area before you clear customs are typically worse again than the ones in the public hall. Some operators run both an airport branch and city branches under the same name at markedly different rates, which tells you plainly what the airport premium is.

The correct behaviour is not to avoid the airport entirely but to use it minimally. Change what you need to get into town and through the first evening, which for most arrivals is somewhere between one and three thousand baht, and do the real changing in the city the next morning. If the office is meeting you, you do not need to change anything at all: the car is prepaid, the hotel takes a card, and the first cash you touch can be at a proper rate. Clients arriving late at night should change a small amount and stop: a bad rate on a small transaction costs little, and on a week's float it does not.

The city counters: how to read them

Thailand's dedicated exchange business is competitive, visible and generally honest. The counters that matter are the specialist money changers rather than bank branch tellers, and in Bangkok they cluster in predictable places: the Ratchadamri and Ratchaprasong block around the big malls, the Pratunam market area, Silom and Surawong, the Sukhumvit corridor around Nana and Asok, and inside most of the major shopping centres. Several of the best known operators are long established chains with brightly coloured branding and boards that are legible from across the street, and they compete on rate publicly because that is the only thing they compete on. Locals and long stay residents use them without a second thought.

What to check before you hand over money is short. There should be a licence displayed: money changers in Thailand operate under authorisation from the Bank of Thailand, and any legitimate counter will show it. The board should display separate buy and sell rates by denomination, because a hundred dollar note and a twenty dollar note do not fetch the same rate. There should be a printed receipt, which you keep. The notes should be counted in front of you and you should count them again before you step away. And you should never, in any circumstance, change money with a person who approaches you in the street, in a bar, or outside a counter offering a better rate. The rate on offer is the bait and the arithmetic is the trap.

Which currency to bring, and in what condition

United States dollars remain the most efficiently changed currency in Thailand and attract the tightest spreads, followed by euros, pounds sterling, Singapore dollars, Hong Kong dollars, Australian dollars, Japanese yen and Swiss francs, all of which the main counters handle daily. Beyond that the market thins and the spread widens, and a client whose home currency is not on the main list is usually better off bringing dollars.

The condition and denomination of the notes matter in a way that surprises people. Larger denominations fetch better rates than smaller ones: a hundred dollar note will be bought at a visibly better rate than five twenties for the same face value, and the difference is not small. Notes that are torn, taped, heavily creased, marked with pen, stained or from an older series may be discounted or refused outright, and this is not counter staff being difficult; it reflects what their own bank will accept from them. Bring clean, flat, current series notes in large denominations, carried in an envelope rather than a pocket, and you will get the rate on the board rather than a conversation about it.

What you will be asked for, and what gets reported

For a small transaction you will often be asked for nothing more than the notes. Above a modest threshold the counter will want your passport, and sometimes a photocopy or a scan of the photograph page, and will record the transaction. Above larger thresholds the counter will complete a form, and the transaction sits inside Thailand's anti money laundering reporting framework in the ordinary way. None of this is an obstacle to a legitimate traveller and none of it should be avoided; the counters that do not ask are the ones to be wary of, not the ones that do.

Two separate rules sit around the border rather than the counter. Currency brought into or taken out of Thailand above the declarable threshold must be declared to Thai Customs on arrival or departure, and there are additional rules on taking Thai baht out of the country, with different limits applying to travel to neighbouring countries. Your own country almost certainly has an equivalent declaration rule at the same sort of level. The thresholds are published, they move, and we do not quote them as settled figures; verify the current numbers with Thai Customs and with your own customs authority before you travel with any substantial sum. The office view is simpler than the rules: if the amount is large enough that you are asking whether it needs declaring, it should not be travelling as cash at all. Wire it.

The channels compared

The bands above are relative, not absolute. Rates move daily and branches of the same operator differ. Treat the table as an ordering rather than a set of numbers, and check the board on the day.

Hotel exchange is convenience, not value

Every good hotel in Thailand will change money at the front desk, twenty four hours a day, against your room key and passport, with no queue and no walk. That is a genuine service and it is priced accordingly. The rate will be materially worse than a specialist counter three hundred metres away and slightly better than the airport. Use it for what it is good at: a thousand baht at eleven at night, a top up on the morning of departure, a small amount when the weather has made walking anywhere unattractive. Do not use it to change a week's float, and do not let a member of staff or an assistant do so on your behalf out of politeness. At a remote island resort with nothing walkable nearby the desk may be the only sensible option; in central Bangkok it never is.

A working routine for a two week stay

• Change one to three thousand baht at the airport, no more, or nothing at all if you are being met
• Check the interbank rate for your currency on the morning you intend to change properly
• Use a licensed specialist counter in the city, in large clean notes, and keep every receipt
• Change in two or three tranches across the stay rather than all at once, so the rate averages out
• Keep the bulk in the room safe and carry a day's float
• Break large notes at a convenience store or mall so you always hold hundreds and twenties
• Leave nothing to change on the last morning; the departure hall rate is the one you set out to avoid
• For anything beyond a holiday float, wire the money properly rather than carrying it

Exchange rates, counter spreads, identification thresholds and currency declaration limits all change, and we deliberately do not state any of them as fixed figures. Verify current declaration thresholds with Thai Customs and your own customs authority, verify the licensing status of any money changer with the Bank of Thailand, and check the day's board before you commit to a transaction.

This briefing is general information, not legal, tax or investment advice. Thai rules change frequently and individual cases differ. Verify current requirements with the relevant authorities, including the Immigration Bureau, the Board of Investment, the Land Department, the Department of Business Development and the Revenue Department, and take advice on your own facts before acting.