What Are the Requirements for a Retirement Extension at Krabi Immigration with 800K in the Bank?

With 70+ immigration offices inside the country there is no one size fits all list of documents. Either go to the Krabi office and get the hand out or post your question on a f/b page related to that area.

Using banked money method the requirements for the money is, 800K baht (or the equivalent) in a thai bank account in your name only for 2 months before you apply for the extension, it has to stay in the account for 3 months after the extension is granted and then the balance can't go below 400K baht for the rest of the year.