How can I disenroll from Medicare Part B without affecting my Social Security benefits while living in Thailand?

You are unable to use any part of Medicare outside the US, so there is no point in paying for part B, as you can not use it outside the US. To disenroll contact the Social Security office in Manila in the Philippines. They will send you a very simple form to end part B payment. After you send them the form back, it takes less than two months for it to take effect, and you start getting the money that was going to part B payment in your monthly payment. The downside to doing this is if you ever want to get back on part B, you can only re-enroll during the enrollment month, and then you are penalised by having to pay 10% more for each year you were not on part B. This means if you didn't get part B for say five years, then if you go back on it, you will pay 50% more as a penalty. I ended my part B payment two years ago, and it means about bt3500 more I get each month in my payment, instead it going to part B payment.

You can drop Part B easily with no special conditions, other than you must accept the consequences of doing so, if you later need Part B but don’t have it.

There is no effect on your SS disbursement, other than there is no deduction to cover Part B.

I dropped Part B because I never will return to the USA, so I’ll never have an opportunity to use it. I’d rather put the money into health insurance usable in the country I actually live in.

But you’d be out of your mind to take advice from a Facebook group on something this important. You can verify this information and read specific instructions on how to cancel on the official USA medicare.gov website, and I encourage you to do so.

I believe part B is mandatory unless you have other insurance. You will have to show you are covered under another insurance

I didn't know that

Can you opt not to enroll on medicare Part B and not affect your SSS pension? Curiously interested, I now reside in Thailand.

I'd contact the SS office in Manila and ask them. They were very helpful when I had questions.