What should non-O visa holders do regarding pending tax declarations in Thailand?

Actually, by Thai law, all Tax residents must file tax return to the local tax offices regardless of paying tax or not. Even, already paid in home country too. declaration of tax residents is a duty. If they do not do this, they do illegal in Thailand. Yes only by law.

Ignore unless compelled.

Zero

Simple - if have evidences that can back up that it is from your income earned/alternatively assets before 1 Jan 2024 there is no tax.

As an Australian afaik our pension from superanuation IS taxed post 1/1/2024. As I could not get a 31/12/2023 statement from Australiansuper, I took my Australiansuper July statement and the daily earnings Jul–Dec 2023 csv file and got AI to work out my balance at 31/12/2023. Also, see here: /2024. As I could not get a /2023 statement from Australiansuper, I took my Australiansuper July statement and the daily earnings Jul–Dec 2023 csv file and got AI to work out my balance at /2023. Also, see here: https://www.rd.go.th/fileadmin/user_upload/lorkhor/newspr/2024/FOREIGNERS_PAY_TAX2024.pdf

Going forward, I’ll keep a record of what I remit into Thailand and when I bust my pre 2024 superanuation amount in decades to come, I’ll need to do a Thai tax return.

Think most are ignoring it I on the other hand have gone to our local tax office and done a return for the last 2 years with both times very little to pay. As you rightly point out many excemptions can be claimed. I'm guessing one day you may see long term visas linked via the Revenue Department I'm 70yrs old don't think I will see it. But just t to have all in order I file a return.

Both times now never used the DTA as no need, plus military pension a bit complicated, as pension is issued as " tax already paid" in my old country.

Its not that difficult to comply with the law. If you want to claim those allowances, you have to actually submit the tax return. The local tax office has English speaking staff and are very helpful. We both had a tax refund so that was nice :-)

What are most people doing? Totally ignoring it, not saying that's the correct thing to do but if you want to know what most people are doing then that is the answer

I have many friends here in Thailand living here all year and none i have spoke to have or plan to do it.

Not sure if they will ever be linked. But I went to my local Dept of Revenue and they treated me so well. She organised my Tax ID number and also did my online tax filing for me since my situation was so straight forward. I did not even ask for help with the filing; she just started asking a few questions and then I was all done.

Keywords are “assessable income” if you don’t have assessable income then there is no need for a Thai tax return.

"Nothing" is the answer

Best ignore it.. a few years ago I had tax refund from my old company I had closed down several years previously this entailed a visit to thai tax office the amount was less than 1000thb to get the check was one of the most painful experiences ever

So unless I am asked I will offer nothing an frankly I don't expect they would even ask

Wait till you are asked

Most people are ignoring it.

Can you share a link to whatever you are referring to please, is it something new?

There are always rumours about tax, but if rumours are all you are talking about and you are not earning any money in Thailand there should be nothing to worry about.

There is no link between visa re-newals and tax