Do I need to leave Thailand to extend my Non-B Work Visa, and what documents are required?

So you get the documents from the school saying you stop work on xx date, you go to the immigration office BEFORE that date, they will cancel your current extension, THEN you apply for a 60 day covid extension (having proof that you will leave in 60 days will help). The immigration office you deal with knows good and well that the UK consulate here doesn't issue the letter. SO you'll either get the 60 day covid extension OR you'll get a 7 day extension denied stamp that gives you a week to leave. THEN you'd have to exit/re-enter the country.

That's what you do, and no one can tell IF you'll get the covid extension or not, you just have to go try for it yourself.

Depending on the immigration office you won't need a British Embassy letter. Apply for a covid extension on your last day without it. Some offices are more lenient. A TM30 showing your address or hotel will be needed.

I think what immigration are implying is that you need to get a letter from your embassy saying you can't travel and they will then give you what's known as a Covid extension. Frankly you have no charge of getting such a letter from the UK embassy. I'd just go cross a border and come back on visa exempt which gives you 30 days and can be extended for a further 30

The British embassy does not issue the letter for unable to travel due to Covid. I know because they emailed me 2 weeks ago when I asked for one. They also said in the email that immigration know that the British embassy no longer issues this letter. I went back to immigration with this information and they told me I need a plane ticket out of Thailand and a reason why I can’t leave now. So I just flew to Phanom Phen and back the next day. Stamped in no problem on 30 day visa exempt.

What you need to do is:

1. within (but as near as possible) your last day with your current job, apply for cancellation of your work permit then cancel your extension based on employment/teaching. You can apply for cancellation several days in advance.

2. At your local immigration office, immediately apply for a Covid extension when you do 1, bring possible required documents as much as you can.

You can try to apply for a Covid extension and I think that was what the immigration office advised you. If IO asks for an embassy letter when you apply for a covid extension and you cannot provide it, your application may not be approved.

IF your covid application is approved, your extension would start on that application day, you still get enough time for your plan.

In the worst case, IO accepts your application but doesn't approve it, and gives you a stamp for 7 days to leave the country. These 7 days also may start on the day of application.

If you cannot talk UK embassy, send an email to ask for a letter for an extension application. They may send you an email saying that they don't issue the letter. A hard copy of this email may or may not work for you. But that is what you can do to follow the advice by IO.

Be ready with a plan of short international travel around.

Attached is general information for the so-called Covid extension.