Requirements for extending single entry Tourist visa at Chiang Mai immigration -
Is the following what you need?
* Copy of passport photo page and current visas.
* 1,900 THB.
* TM30
* Forms TM.7 & STM.2 [I don't know which form..maybe both?]
TLDR : Answer Summary
To extend a single entry Tourist visa at Chiang Mai immigration, you will need: a copy of your passport photo page and current visas, 1,900 THB fee, TM30 form, and forms TM.7 and STM.2. It is also recommended to bring a passport-sized photo.