How long before and after a retirement visa renewal must the funds remain at 800,000 baht in Thailand?

It’s just not worth screwing around with. Park the 800k and forget it until you change visa.

I understood under the new rules for OA visa the money sits permanently in the bank. The reason is you require 3 months before a 3 months after your application. And because you apply every 12 months this is the result.

Nakhon Phanom immigration insisted on 3 months before extension application. I was three days short and had to go back the following week. Always check with your own office.

Never can go down 400k

Three months after you get your 12 month extension and 2 months before you apply for a new extension it has to be at least 800k

For an extension based on retirement, the bank account must show 800,000 for 2 full months before applying for the extension (not before the extension ends, but before you submit the application) and then it must remain at 800,000 for 3 months after the extension is granted. Some immigration offices may differ on how they count this and whether it is 3 months after the extension is granted, or 3 months after the extension date.

So generally it will be 5 months that the account must be at 800,000, but could potentially be up to 6.5 months since you can apply for an extension 45 days early at many offices.

The rest of the year the balance cannot drop below 400,000.