The Immigration Bureau (Police) is where to extend visas and do re-entry permits. Helpful and Friendly Staff.
Please dress politely when visiting there.
As one should at all times in Thailand. It is located between the airport and Central Airport plaza.
There is a photocopying service in the back of the property in the restaurant should you need it.
Chiang Mai Immigration 71 Moo3 Sanambin Road T. Suthep,A. Muang Chiang Mai
General Chiang Mai office 0-5327-7510, 0-5328-2532 0-5327-7510 Airport Arrivals office
Chiang Mai Airport 0-5327-7190, 0-5327-7180 0-5320-1685
http://immchiangmai.com/site/ Mostly in Thai