What is the process for obtaining a Volunteering Visa for Thailand, and what should an invitation letter include?

Yes I do

DISCLAIMER - this is what I did, you'll need to check your own requirements with relevant the consulates/embassies.

This you will need:

-Thai Charity registration documents - every page signed by owner/manager

-passport copy of Thai owner/manager

- invitation letter from owner/manager with your full name and passport number stating that you will be doing voluntary work for no monetary reimbursement and that you need a non- imm O visa type. ( this attachment should have the ID of the signer also )

- if you are volunteering in a specific field then a graduation certificate (I gave a copy my vet degree one)

- flights into and out of country

- bank statements

-passport scan and appropriate photo

In the UK I filled out the application online for a single entry non-imm O volunteer then sent all the documents to the embassy via a visa agency. Paid £65 I think.

This gives you a 90 day single entry.

You can extend to multiple entry once in country for about 3000THB and more paperwork. To extend this visa you need to apply for a work permit (that plus an extension is another 12kTHB) which gets you to 6 months total at this point.

Then another 3 month renewal until the 3re renewal when you can get an annual volunteer visa(I havent got that far yet so dont know costs).

Hope this helps and that you will be able to actually use this type of visa to get into the country some time in 2021.

One basic question. Is the owner of the company, who is your friend, Thai, or a foreigner, as that makes a huge difference in that company's ability to sponsor a visa for a foreigner, even on a volunteer basis.

No one knows what the ‘new normal’ situation will be with visas/exemptions for tourists to enter Thailand. Or when the Thai government will consider applications for other visas from outside (beyond what has already been announced re Elite etc). If you are outside Thailand the only thing you can do is wait and see. It’s going to be many many months.

Laying aside the current situation, very few nationalities can get "visa on arrival". Perhaps you're confusing it with "visa exempt" entry?