I will be traveling on U.S. passport arriving and staying in Chiang Mai on visa exempt status which I understand is obtain at airport in Chiang Mai, is free and is good for 30days. I plan to stay @ 60 days. Where can I get an extension in Chiang Mai - what is cost - what do I need to show in terms of documents? Do I have to wait until the last day or two of the initial visa exempt to get an extension allowing for the total of 60 days or can I get it after say, 2 weeks and have it "start" after my visa exempt expires thus still allowing a total stay of 60 days. My thanks in advance.
TLDR : Answer Summary
Travelers on a U.S. passport arriving in Chiang Mai on a visa exempt status can stay for 30 days, but can extend their stay for an additional 30 days at any immigration office in Chiang Mai. The extension costs 1,900 baht and requires several documents: a passport-sized photo, a copy of the passport (with entry stamp), and the filled extension application form. The extension can be applied for anytime during the initial 30 days, not just on the last day before expiration.