Can anyone advise the best approach to sending 400k AUD to our Bangkok Bank Account for property purchase in Thailand please?

Bank to bank the only safe method, it's costly as you lose on the exchange rate but that the cost we have bear...

25 minutes ago, ezzra said:

Bank to bank the only safe method, it's costly as you lose on the exchange rate but that the cost we have bear...

That is the way we did it (from US, not AUD though) for the reason specified but also for the traceability, given Thailand's insistence on the money being demonstrably from overseas.

Make sure to tell your bank to send the money in AUD so that it will be exchanged within Thailand to THB.

Don't any bank exchange it before it arrives in Thailand!

That is the rule for buying property in Thailand. 

There are also a couple of websites with detailed information. Just search for them.

For that size Wise isn't a good option plus people cock up the transfers, just do normal A$ bank transfer not THB as suggested above

A normal SWIFT bank transfer. Nowadays you can do it with your online banking app. (send $AU)

Wise and similar can have the dramas of showing money from overseas etc, 

Wise is better exchange and fees, for smaller amounts but over a certain amount swift ends up better or around the same, due to a fixed fee.

Swift is instant when both banks are open (morning through to early afternoon from Oz). Monitor the BKK TT exchange rate on their website and send when its good.

 

Swift transfer, your bank in Australia to your Thai bank account.

 

Obtain a foreign transfer certificate from the Thai bank for the amount evidencing the inward foreign currency transfer for property purchase.

 

Later this certficate can be used to transfer the money back out again.