What do I need to know about obtaining a retirement visa in Thailand as an Australian expat?

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You can open a Thai bank account on any visa as long as you got proof of Thai address and a good reason for opening

You can't get a retirement extension on a visa on arrival, get a Non O Visa in Aus with a view to retirement, you then extend that yearly as the retirement extension of a Non O. No such thing as a retirement visa. I would get a 1 year Non O which can last 15 months, plenty of time then to get things sorted out.

If you are in fact in Queensland like your profile states, I'd contact the honorary consulate in Brisbane first to see who they'd suggest you use to get it.

I didn't mean to confuse you with that oh-so long post, sorry :/

You are confusing a couple different things. There are a few ways to get what you're wanting.

Here's how it breaks down;

Option A (the best and easiest course of action for you):

You apply for a year-long multi-entry Non-immigrant Type O-A (Long Stay) visa from a consulate in Australia before you come here. I dunno if the honorary consulate in Brisbane issues them but I know that one of the consulates there does. Applying for this visa requires you to show proof of adequate finances in a bank in Australia and a police report. I am not sure but I believe only Canberra or Sydney can issue them.

As I said earlier that visa is valid for a year, it allows unlimited entries and exits into the country with each entry getting you stamped in for a complete calendar year.

Option B (doing it all inside the country)

You come in on a 30 day visa exempt stamp or a 60 day tourist visa stamp. You open a bank account here transfer in the required funds and go apply for a 90 day Non-Immigrant Type O visa. It will go under consideration for 14 days and then you go back to get the new visa & new 90 days stamp inked into your passport. Once you have that you wait until you have 45 days or less left on that stamp and go to the immigration office and apply for a yearly extension of stay based on being over 50 (retirement), by meeting the financial requirement and by having the money "seasoned" (in the account in thailand) for 60 days before your application for a year extension. After you get the extension granted, if you're going to leave/re-enter thailand you'd need to buy a re-entry permit too.

Option B requires 3 visits to the immigration office, once to apply for the Non-O visa, once to go get it inked into your passport and once again to apply for the yearly extension of stay.

Equivalent in an Aussie bank works for Thai consulates in Australia.

Tod is the man! Always get a visa prior if you can!

you should look into getting a Non-Immigrant Type O-A visa from one of the thai consulates in Australia BEFORE you wing your way here. You don't need to show any money in a bank in thailand, no residence here, just follow the directions from the consulate. That visa will give you unlimited entries in thailand for the duration of the visa and each entry will stamp you in for a full calendar year.