Like I said, I have little risk of paying any Thai tax and as it turned out I learned of some advantages to my US tax obligations due to the Thai-US tax treaty that I wouldn’t have known about if I hadn’t talked to the tax firm.
The tax rule change came into effect Jan 1, 2024. It has always been the case that you become a Thai tax resident after 180 days. Don’t want to file a tax return? That’s up to you. Good luck with that.
I'm working with a tax firm and plan to file a Thai tax return for 2024. Like in the US, I would think that if you don't file the return no one is going to magically show up on your doorstep. I stopped filing tax returns in California in 2019 and only this year did they notice it and send me a letter about it (I got it cleared up OK). I doubt that Thai immigration is going to know anything about your tax status. One could think up all sorts of nefarious ways they could catch you but I would think you could fly under the radar for a long time or forever. However, technically you may actually owe taxes in Thailand and there could be some time in your future when this catches up with you.
The tax treaty with your home country is really going to determine your tax liability. They are probably all pretty similar with regard to avoiding double taxation. I learned some interesting things about the US-Thai treaty that benefits me. I wouldn't have know about it if I hadn't talked to the tax firm.
Filing a tax return is an easy decision for me because my tax liability in Thailand is essentially zero because I have an LTR visa but I will file for 2024 just to see what is going on. I tend to follow the straight and narrow.
Years ago I got one through UPS. I went to an office, had my fingerprints taken, and filled in a form. I got my report a week later and it satisfied my application for an OA visa. Check to see if UPS offers this service in your area.