Since the original post about this has commenting turned off, this is in reply to Martin Pol arguing with many of the most long time contributors of this group because he refused to believe all the people who tried to tell him that the 20k proof of funds requirement is real. I normally wouldn't bother but he was so rude to so many members that I feel it is important to put this info out there:
Your chance of being asked is probably one in tens of thousands but if you are asked and can't show it, it is pretty surely a certain denial. People who say they have never been asked are the equivalent of saying you’ve never been searched for drugs… but if you are, the regulations are quite clear about what happens. You are typically only asked if the immigration officer already believes there is a reason to deny you due to not believing you are a genuine tourist, based on your previous entry and stay history. If asked, it must be shown in CASH only, and cannot be through bank statements, credit cards, online banking, ATM cards, etc. There are NO ATMs airside in international arrivals before you get to immigration, so you can't withdraw cash upon landing, so you must have the cash with you already when you land. You MAY get lucky and get an immigration officer who takes pity and will escort you to an ATM in baggage claim past immigration to withdraw the cash, but this is not actually allowed, and there are posts from people who say they begged the immigration officer to let them go to an ATM to get the cash and were refused and had to fly home.
Here is the regulation about the proof of funds requirement from various Thai consulates that I compiled a while ago in response to another person that refused to believe there is such a regulation. Please note that the info below is about visa exempt entries as that was the post I was responding to at the time, but visa on arrival (which is a totally different entry scheme that only less than 20 nationalities qualify for) has a similar but lower 10,000 baht per person/20,000 baht per family requirement. Also, some links may no longer be active since consulates change their web page URLs from time to time, but you can read the quoted info from each consulate:
1) Royal Thai Embassy, Washington DC (USA):
[members only]/
"Travelers entering Thailand under the Tourist Visa Exemption Scheme must possess adequate cash of or equivalent to 20,000 Baht per person or 40,000 Baht per family."
2) Royal Thai Embassy, Doha (Qatar):
[members only]
“Travellers entering Thailand under the Tourist Visa Exemption Scheme must possess adequate cash of or equivalent to 20,000 Baht per person or 40,000 Baht per family.”
3) Royal Thai Embassy, London (UK):
[members only]
“please make sure that you are in possession of a passport valid for at least 6 months, a round-trip air ticket, and adequate finances equivalent to at least 20,000 Baht (450 pounds) per person or 40,000 Baht (900 pounds) per family.”
4) Royal Thai Embassy, Manama (Bahrain):
[members only]
"Upon arrival you may be asked to present round-trip air ticket and proof of adequate finance equivalent to at least 20,000 Baht per person or 40,000 Baht per family."
5) Royal Thai Consulate, Los Angeles (USA):
[members only]
“Travelers entering Thailand under the Tourist Visa Exemption Scheme must possess adequate cash of or equivalent to 20,000 Baht per person or 40,000 Baht per family.”
6) Royal Thai Embassy, Bern (Switzerland):
[members only]
“Foreigners entering Thailand under the Tourist Visa Exemption category must provide proof of adequate funding for the duration of stay in Thailand at the port of entry (i.e., traveler’s cheque or cash equivalent to 20,000 Baht per person and 40,000 Baht per family)”
7) Royal Thai Embassy, Vienna (Austria):
[members only]
“Travellers entering Thailand under the Tourist Visa Exemption Scheme must possess adequate cash of or equivalent to 20,000 Baht per person or 40,000 Baht per family.”
8 ) Even foreign embassies list this requirement for their citizens traveling to Thailand, such as this example from the Luxembourg embassy in Bangkok : [members only]
"In addition, the immigration authorities may be required to present the equivalent of THB 20,000 per person in cash."
9) Here is a detailed article about this same requirement from a legal website [members only]/
Example quotes from Facebook posts in various Thailand travel groups from people denied:
1) Her airline even offered to take her to the ATM machine to withdraw 20,000 Thai baht...Immigration said NO.
"Hello I've been denied to enter the Kingdom (exemption) with the reason my old passport had many border stamps even all my documents are completed.
...Then he asked me the cash which I forgot to get cos I thought I would be picked up by hotel staff for quarantine so I dont need cash.
...and I showed them my money from my thai bank acc that I could draw right away.
...But the officer didn't care and denied me and managed my return to my home country.
2) Two days ago I was denied entry at Don Muang Airport for not carrying 20,000 baht on me. They kept me in the detention area for 16 hours before I flew back to Laos. I have had a lot of visa exempt stamps over the last 3 years but ive also had 2 work permits.
3) I have been asked to show cash, not sure that would have granted me entry, however, I failed to show the 20k, there were ATMs downstairs just 50 steps away, I could have sent my girlfriend to withdraw for me, but they were too busy filling papers to listen and when they finished I was escorted to the deportation office.
The only option they gave me was to buy a ticket for the first flight back to Osaka and wait 2 days in detention room for it.
4) I had an active ED visa, went to Suvurnabhumi and got a re-entry permit and left for Bali. Came back 5 days later and then got denied for not having 20k baht on me and the IO saying that I'm working as a teacher.