Do I need to maintain 500k baht in my bank account after my Thailand visa is approved?

Once your visa is approved, you are free to use your money as you wish. However, if you plan to apply for an in-country extension after six months, you will need to show that you have 500k baht in your account for that extension. It's important to note that this amount does not have to stay in the account for three months prior to your extension; just the current balance is required.