Is medical insurance required for the Non-Immigrant O (Retirement Extension) visa in Thailand?

If you ask many people, you'll get many different answers. That's why it's generally better if you only ask our group. You've already received the correct answer to your question. You don't need health insurance for the Non O Retirement Visa. But apart from the visa, it's very important to have health insurance in Thailand, at least for emergencies.

Not required.

Go to Immigration then and ask

If your initial visa was Non-O for being over 50/retirement for 90 days, there is no insurance requirement for you to apply for a 1-year extension based on retirement.

On the other hand, if you entered Thailand on Non-OA and continue to stay from that visa, you must meet the mandatory insurance requirement to be able to apply for a 1-year extension based on retirement.

Sometimes people mix Non-O visa based on retirement and Non-OA by same “retirement visa” words, and it leads confusion.

Not required for Non-O

Insurance is NOT required for the non O

There's NO health insurance required for the Non O Visa as a retiree.

You are confusing the OA visa for retirement - obtained in your home country, which does require a US $100,000 health insurance policy.