What is the process for applying for a retirement visa in Thailand from Australia?

make a spreadsheet with everything  you will spend your money on. Be very, very detailed. Once you get that number double it. If you have that, then you can come.

I did it last week. As I live in NSW the evisa site ended up having me apply at the Thai Consulate in Sydney. When applying for the visa choose other, then choose from the drop down menu, retirement over 50 pensioner. You must show equivalent of 800k in your Aussie bank account which I had. This visa is a non o retirement and costs $120 aud and that will be a 90 day visa. I will extend that when I am in Thailand either by putting that 800k in my Thai bank account or by using an agent. Good luck!

You can get a oa visa from your own country

You don't need to have 0 the in your thai account

But you need police check from your country

Full 1 year insurance from your home country

Also 1 year insurance from a thai company

Health certificate from your doctor

This will get you a multiple entry OA visa valid for 1 year

Also exit flight and proof of accommodation for the whole time

It sounds complicated but really isn't

You need to show the equivalent to 0 thai baht in your own currency

I do it this way because of the interest I get in my home bank is way more than a thai bank

Apply for the initial non O visa based on retirement, from the official Thai e- visa website.

Easiest option is to apply for a non O retirement visa which gives you 90 days and then extend it for one year when in Thailand. There is the OA option but that requires more such as obtaining insurance, health check.