*** The best way is to show up in Thailand on a “90-days single entry Non-Imm-O Family Visa”. It will get you stamped in for a 90-days stay permit. Within this 90-days period, you have plenty of time to arrange for the application to the “1-year extension of temporary stay permit”.
The important fact is, that entering on this visa-type enables you to get a Thai bank account opened.
If you enter on a tourist visa or visa-exempt, you cannot get a Thai bank account opened any more since February 2025.
In order to apply for the “90-days single entry Non-Imm-O Family Visa” through the online E-visa system at the Royal Thai Embassy of your home country, you can
EITHER
use proof of income of a monthly minimum of 40.000.- THB equivalent, by using your original income documentation,
OR
you can use a deposit of a minimum of 400,000 THB equivalent in your home country currency, or on your home bank account, or on your Thai bank account (if you got one), or just anywhere in the World – as long as the account is in your sole name.
Most Thai embassies will require 3 months of account statements for the visa application. You need to check the website of the embassy you will use for the exact info.
*** For the application inside Thailand to the “1-year extension of the stay permit based on being married to a Thai Wife”, the financial proof will be slightly different. On Immigration inside Thailand, you cannot use any original income documents from your home country.
If you are a citizen of a country whose embassy in Bangkok does not issue a certified “income affidavit” any more (which are the embassies of USA, Canada, UK, Norway, Sweden and Australia) you would need the minimum of 400,000 THB deposit.
If your embassy still issues a certified affidavit of income, you can use it for the financial proof. You would need a certified monthly income or pension of a minimum of 40,000 THB.
For British, Canadian, Norwegian, Australian, Swedish and U.S. citizens, there is no other way around than depositing a minimum of 400,000 THB in your Thai bank account.
*** After been issued the 1-year extension of stay, you can theoretically take your 400,000 THB out of your bank account.
There is a fee of 1900 THB for the application to a 1-year extension, and you can theoretically do it all by yourself. You are free to accept the help of an agent for the simplified legal service.
On the day of application to the 1-year extension, the 400,000 THB must have “seasoned” in your account for two months, and this has to be confirmed with the “bank letter of guarantee” (in Thai: rab roong thanakan), an ATM receipt of a small withdrawal, and an updated bankbook.
After been issued the “1-year Extension of the Stay Permit based on Being Married to a Thai Wife, you can take the deposit out of the account.
Yet before the application to the next “1-year Extension of Stay”, a minimum of 400,000 THB must again have seasoned for two months.
On the day you get issued the “1-year extension of stay permit”, you should buy a re-entry permit.
A re-entry permit will keep your 1-year stay permit alive and valid in case you want to travel around and exit Thailand before the expiry of the extension.
A single re-entry permit is 1000 THB on Immigration. A multi re-entry is 3800 THB.
On a multi re-entry permit stamped, you can exit and re-enter as many times as you wish during the whole 1-year stay permit period.
Good Luck with your application.