Hi.

can i convert tourist visa to NON B in thailand without leaving the country? with all the supportive documents provided by the company which is going to hire me.

You will need a work permit, which you can not get without non-B, catch 22.

In general, the process is:

• Get documents from company and apply for work-permit at Labor Dept
• Get "work permit application letter" from Labor Dept
• Take documents from company plus this letter abroad to get a Non-B Visa (Single-Entry - 90 days permitted-stay received upon entry)
• Return on Non-B Visa
• Take documents from company and passport with Non-B to Labor Dept and get work-permit
• In the last 30-days of the 90-days permitted-stay, apply for a 1-year "extension of stay" at your local Immigration Office

In theory, the "work permit application letter" could be used to apply for a conversion to a Non-Imm entry at an immigration office in-country.  If your company is very well-connected, then maybe they can get your Tourist-type entry "converted" to a Non-Imm entry while you remain in the country - but this is not common. 

Edited March 17, 20188 yr by JackThompson

13 hours ago, EHSAN said:

can i convert tourist visa to NON B in thailand without leaving the country? with all the supportive documents provided by the company which is going to hire me.

You can if your employer applies for a work permit and obtains a work permit application approval letter from the Department of Employment.

Requirements are here. https://www.immigration.go.th/content/service_72

That is the list of required documents to convert at Phuket Immigration.

In the past you used to need to have 30 days remaining validity on the TR in order to be able to change in country in addition to the work permit application approval letter mentioned by @ubonjoe who probably knows if the 30 day requirement still applies.

13 hours ago, Yme said:

In the past you used to need to have 30 days remaining validity on the TR in order to be able to change in country in addition to the work permit application approval letter mentioned by @ubonjoe who probably knows if the 30 day requirement still applies.

As far as I know it has never been 30 day. Some time ago it was 21 days but they changed it 15 days.

From the immigration website I posted a link to in my previous post.

Quote

1. The application must be submit more than 15 days before visa expiration and, in case of overstaying in Thailand, application could not be submitted.