If you’re here for 180 days plus in a tax year, just submit a tax return then as is required by law. Include all your exemptions and credits. Sure it will be fine.
Most expats here are living on pensions so the “before Jan 1 2024” rule is irrelevant to many. Additionally, many western pensions are NOT COVERED in DT agreements (USA is). This dual taxation residency argument is also irrelevant under thai tax law and only applies to a very few countries anyway.
lot of incorrect statements there. Fact of matter is you’re here for over 180 days in a calendar year, you become tax resident and if you bring in over 120,000 baht it’s assessable for thai tax . Thai tax personal allowances are generally much less than the west so the likelihood is that you’ll be paying some (albeit pretty insignificant in a lot of cases) thai tax .
Your answer to his question is irrelevant. Just because he has paid tax in Singapore doesn’t exempt him from Thai tax under the double taxation agreement. Which is what his question is implying. 180 day rule still applies in thailand for tax resident purposes.
Irrelevant. He’s Thai tax resident if he’s been in Thailand for 180 days or more in a calendar year. He needs to file a tax return in Thailand if he has brought in assessable income in 2024 (over 120,000 baht for a single person).