That's a very generous amount without having to declare - most countries limit undeclared to about AUD10,000 but if you declare there is no penalty or tax. Given USD is about AUD31,000 it would give a better exchange rate to bring in AUD30,000 and the balance by SWIFT .
Hi Donald. You were the one that said you can't carry cash, implying it was an option for you. Anyway, I guess it is how you carry it and your assessment of the risk. As to the allowable amount, there is no limit on how much you can take out of Australia but maybe there is a limit on how much you can take into Thailand? With conversion of AUD37,500 to THB there will be a very large difference between converting it at a currency converter in Thailand and the other ways you mentioned: it is even significant when I have carried AUD5,000. Finally, I understand it is the 21st Century but that does not mean you throw away a significant amount if not necessary.
Not sure why you say you can't bring that much cash? I always take cash to Thailand and get the best exchange rate from the money changer at Central, Lad Prao. If you do transfer from Aus bank to Thai bank, you will probably get the best exchange rate by transferring AUD, not THB.
I had a close friend who worked with Border Force. He assured me you can and gave me a copy of the declaration form in case I needed to take $10,000 or more. If you don't have one filled in, when they ask if you are carrying $10,000 or more and you answer yes, they will take you aside and have you complete the form. Before you give misinformation, go to the web site and check.
There is no limit on cash you can carry leaving Australia. If you have AUD10,000 or more (or equivalent in another currency) just declare it and you are good to go,