1) there is a grandfather clause.
The effect of this clause is that you can bring money into Thailand after 2024 without being liable for Thai tax as long as it was accrued before Jan 1st 2024
2) dual taxation treaties:
Each one is different so you need to either read your countries treaty extreme carefully (Thai tax officials will not know the details of every one so you must know them to check that you aren’t taxed if the treaty has an exemption)
An example (I haven’t studied the treaty as it doesn’t affect me so I maybe mistaken) USA citizens have some pensions that are exempt from Thai taxation.
dual taxation treaties generally work by your filling in a tax return in your home country, you are charged tax. Subsequently you fill in a Thai tax form. Your tax liability is assessed.
If you have paid more tax (or the same amount) in your home country you have nothing to pay in Thailand
If you have paid less tax in your home country the amount of tax paid is deducted from your Thai tax due and you are required to pay the difference
Just because you have paid tax in your home country DOES NOT exempt you from declaring and paying tax in Thailand
This is a general overview and is based on advice from a major international tax advisor
Advice specific to a U.K. national
- Overseas income in the form of interest, dividend, gains, rent and pensions will be subject to Thailand income tax at your marginal rate of tax IF brought into Thailand
- If the money is kept overseas and spend whenever you are outside of Thailand, you would not need to report this income for Thailand tax purposes
- For the 2024 tax year and each subsequent tax year, you will need to file your Thailand tax returns by March of the following year e.g. for the 2024 tax year, the filing would need to be done by March 2025
- For capital gains, there will be an exemption on part of the capital gain before the rest is subject to UK income tax
- Any assets sold in a tax year, which are at a loss, cannot be used to offset a gain achieved by selling an asset with a gain in that tax year