You cannot use companys NOT on the approved list for extensions of an O-A visa, no matter if you could get the certificate or not. The certificate is only of any use to obtain a NEW O-A visa OUTSIDE of Thailand for a company NOT on the approved list.

No, you cannot extend your type of Non b visa

There are 4 category of Non B visas.

1) Business

2) Working (Accept teaching)

3) Teaching

4) Intership

Take your pick of the Non b visa to suit your needs.

Not a lot of use at all really

Non-Immigrant Type B (Travelling to Thailand for business purposes e.g. meeting, exhibition - single and multiple entries)

Letter confirming employment details from an employer signed by an authorised person stating the business purpose that the company will dispatch the employee to Thailand

Copy of ID card or passport of the signer (authorised person who signed the employment letter)

Invitation letter from a company in Thailand

Business license of the inviting company in Thailand with the company’s stamp and authorised person’s signature

Financial evidence e.g. bank statements, proof of earnings, proof of sponsorship from a third party

@Robert ******

can you obtain a WP on b visa issued to conduct business? (Not non b to work)

@Benjamin *****

Hanoi actually says this in regard of a Non b for teaching. It's not a Thai police clearance they may or may not ask for

'

- Police certificate verifying that applicant has no criminal record or equivalents or letter issued by authorised agencies in applicant’s country. (The requirement of the submission of such police certificate is optional. The applicant must submit it if consular officer requests he/she to do so. This requirement is effective as from May 2007)

Also 7 day refused extension of stays, invariably become live the day they are applied for and NOT post dated and some offices refuse them completely.

Was posted and replied to earlier.

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Bulgarians can also get VOA at some land crossings from Laos, Cambodia, Myanmar and Malaysia.

This is a very good link with information for Bulgarian passport holders.