Depends if you keep Australian Tax Residency. In that case it's not taxable in Thailand. To say it's "untaxed" is not quite true. Super contributions are taxed at 15% when they are paid in, and the Super Fund is taxed, the taxation comes from members funds. It's just the final amount which goes to the recipient doesn't have to be declared if the recipient is over 60. Good reason to retain Australian Tax Residency. So many tax perks
Where does it state that on the tax return form? The tax return form only has spaces for "assessable income" which the pension is not, so there's actually nowhere to put it.
That's my position. Fifteen years here, the rule change (delaying remittance until a later year) doesn't affect me, as I've always transferred pension money the same time I received it. Never had to get tax ID or file a return. As many countrys' DTAs state pensions only taxable in "country of residence" - I retain Australian Tax Residency - it wouldn't be taxable anyway. So my head is very firmly in the sand and will remain there until the Thai tax office issues clear instructions circulated amongst expat communities. There's a lot of doddery old farts out there never use the internet and have no idea of these changes. I can also see a clear "amnesty" for a year or so, until everything is settled and communicated.
All income won't be taxed. It's dependent on each individual circumstance. A person might be a tax resident in another country which would take precedence or might only transfer pension money which may be non-taxable in Thailand. Too many variables