The Thai Currency.
The currency of Thailand is Baht. It used to be linked to the US Dollar but now floats and it's exchange rate changes by the hour or day against a basket of other currencies. At the time of this writing the Thai Baht is stronger than is has been for many years.
Notes and Coins.
Currently there are 6 Coins minted:
25 Satang, 50 Satang, 1 Baht, 2 Baht, 5 Baht, 10 Baht.
There are 100 Satang in 1 Thai Baht but you will rarely find anything costing less than 1 Baht so you ignore them.
Currently there are 5 Notes in print.
20 Baht, 50 Baht, 100 Baht, 500 Baht, 1000 Baht.
There is also a 10 Baht bill (rare) in circulation
Thai notes and coins (2 baht not shown).
Changing my money before coming to Thailand.
Basically the answer to this is Don't. You might lose as much as 10% if you do this.
There are two reasons why you get a better exchange rate inside Thailand than outside.
- On-shore vs Off-shore rates (see below or THB - Now Have a 2-Tier Market by K2)
- The Thai baht is not a "world currency", hence foreign banks have a higher expense ratio keeping them in stock.
If you come from a country with a currency that is not readily accepted in Thailand you may want to exchange to US$, €uro, A$, UKŁ, etc.
Off Shore Rate.
This is the rate for Thai Baht being sold outside of Thailand. Quite naturally any bank outside of Thailand that is holding Thai Baht is going to want to sell it and make money for themselves.
On Shore Rate.
This is the rate quoted when you inside Thailand and you can't get this rate until you get here. Banks and money changers still need to make their percentage of profit for providing the service but as Thai Baht is readily available here they are happy with much lower profits of around a half to one percent.
Thai Baht required on arrival
It is always convenient to have local currency on arrival, but not necessary.
You are going to arrive at an airport and you can be certain that money changers or ATM machines are going to be open at any hour. They are fast and efficient but check you have been given the right amount. Do bring some cash from your home country (or a major currency) and don't worry about the rates being lower than on the streets as in fact the airports offer rates as good or even sometimes better than the streets here. Travellers cheques are also widely accepted.
Travelers Cheques
Generally you will get a slightly better exchange rate using travelers cheques than cash. Do keep in mind that there may be a per cheque fee (i.e. 33 baht) and depending on you home bank affiliation, you may pay a fee to purchase the cheques. The big advantage of TCs over cash and even ATM cards is that if you lose TCs or they are stolen, they will be replaced in about 24 hours, provided you have the serial numbers available.
Credit Cards
They are widely accepted here but beware, as many places will charge you around a 3% penalty for using them. Shops and many outlets including some hotels just don't like credit cards as the credit card companies charge the seller also. Of course this is against the credit card companies rules but that argument will get you nowhere unless you can actually prove you were penalised and then you can take that to the credit card company and ask for a refund which is likely will be given if you have the proof.
You can however use credit and bank cards in general to draw money at Thai ATM's and banks but you might be charged by your card company for a cash withdrawal.
Also beware of credit card fraud as like everywhere this does happen here so make sure your cards are insured against fraudulent use and theft. Keep them in the room safe or hotel safe along with your cash and valuables. Don't carry large sums of money around with you or items like cards unless you need them. Theft is not common here but it does happen.
ATM Cards
ATM and credit cards are often one and the same card.
A couple of additional notes specific to ATM transactions. It is not uncommon for banks to put a block on ATM cards used in certain countries if the bank has not been notified in advance. The block may be instant and by default or it may be after a transaction or two. Always call you bank prior to your trip and advise them that transaction in Thailand (etc.) in a given period of time is to be expected. Even then, banks some times screw up, so having two cards link to different accounts may be advantageous.
If you worry about fraudulent use if the card should be lost, ask the bank for a plain ATM cads, with no credit-card affiliation to Visa or Master Card. These cards can only be used with a PIN code.
Last, be aware that fraud can be right at the finger tip at an ATM machine. The pictures below needs little explanation:
Thai Bank accounts.
Getting a bank account here is, by some reported to be, fairly straight forward even for a visitor (but it can take hours)**. This can be a good way to get money into Thailand. When your foreign currency arrives in your Thai bank account you will be charged between a half and one percent from the better ON SHORE RATE as long as it arrives in Thailand as dollars, pounds, Euros, etc. You will be given an ATM card and possibly a bank book as well. You wont get a cheque book or credit cards as a visitor but the ATM's are everywhere so you can get at your money easily.
This is really only practical if you are a regular visitor though and some banks charge monthly bank charges for just having an account. You will be also charged 20 Baht for each withdrawal and some ATM's only allow you 10 or 20 thousand baht per transaction, with limits on how much you can withdraw in any one day from ATM's. On holidays the ATM's can also run dry so make sure you get your money early.
** It is, however, not uncommon for a bank to decline opening an account for "customers" with tourist visa. If it is important to open an account, simply try another bank. Some have reported that smaller branches are more accommodating.

Personally I travel to Thailand with some Thai currency left over form the previous trip, about $1000 in cash and at least 2 ATM cards linked to two different accounts. Rarely do I use any of my cash; I keep it for emergency.
Credit: Much of this post was written by Hilly at the Secrets Board
