Now this is a single report only so take it as that - a single anecdote. It is not confirmed policy and may be only a single bank manager implementing it at their branch.
In another thread about taxation in another group a guy tried to open a bank account yesterday and was told he needed a TIN (Tax Identification Number).
If this becomes standard bank policy the cat will be truly among the pigeons - especially for those on visas other than DTV.
TLDR : Answer Summary
An anecdotal report suggests that a foreigner was asked for a Tax Identification Number (TIN) when attempting to open a bank account in Thailand. This may not be a confirmed policy and could reflect the practices of a specific bank branch. Comments indicate mixed experiences, with some suggesting that TIN requirements may not yet be enforced universally. The involvement of taxation aligns with broader efforts by Thailand to regulate the financial activities of non-citizens.
DTV VISA RESOURCES / SERVICES