I have a limited company in Hong Kong to which I am the sole director, but live and work in Thailand all year.
I'm paying myself a salary from the Hong Kong company to an account in Thailand via a local company in Chiang Mai. So I'm a tax resident in Thailand, as I pay income tax and social security monthly.

 

But I can see I could also pay myself director's fees to an oversea account (my personal account in Hong Kong). Would this income also be taxable in Thailand? I've read oversea income is not taxable in Thailand unless repatriated within one year. So I understand the director's fees would not be taxable in Thailand. Am I understanding this correctly? Thanks in advance.

If you are a Thai citizen that Hong Kong income would be taxable. But if you are not a Thai citizen your Hong Kong income is only taxable in Thailand if it is remitted to Thailand in the year it was earned.