Los Angeles consulate only gave me a 90 day single-entry non-immigrant O visa and said that I would need to have it extended while in Thailand. I need to both request permission to leave the country on the single entry visa, and also request the one year extension. I'm having a hard time figuring out what is needed in order to extend my 90 day visa for up to one year, and also how to change it to a multiple-entry visa. Do I have to go to Bangkok to do this or can I have this extended in Chiang Mai or Mae Sot? What documentation is needed? Thank you very much for your help.

Sounds as if you need paperwork from your NGO and work permit to make an extension of stay for one year at your local immigration office.

Before your permission to stay expires apply for a work permit from the Labor Department. You are required to have a work permit for employment in Thailand. With the receipt for the work permit application in hand, go to a local Thai embassy or consulate and apply for a multiple-entry non-immigrant "B" visa. Return to Thailand with the "B" visa, get the work permit from Labor Department, and then apply for a 1 year extension of stay based on employment from immigration. You must qualify for the extension of stay based on your employers corporate structure, tax information, and your salary. If the work is associated with a Thai university the paperwork will be less onerous.

Edited November 8, 201015 yr by InterestedObserver