Is health insurance required for entering Thailand on a tourist visa?

Not a legal requirement but you should definitely have it in my opinion.

No. I just give you the answer without all the other advice you didn't ask for 🤔

As of October 1, 2022, Thailand lifted its mandate requiring tourists to have health insurance for entry.  Therefore, obtaining health insurance is not a requirement when entering Thailand on a tourist visa. However, it is highly recommended to have travel insurance that covers medical expenses, as healthcare costs can be significant in case of illness or injury during your stay. 

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Not required legally but you'd require it if sick or in an accident and need costly treatment.

It is not a requirement. Though you are advised to have travel insurance for your own peace of mind.