I was unable to open a bank account in CM without a Certificate of Residence. It takes 7 days for immigration to mail one to you. Then, depending on how you do it, transferring
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0 baht from abroad can take many days. You should plan on getting an extension.
0 in a bank. It must be transferred from outside Thailand. Then you apply for a 90-day visa. Then you wait 2 months. Then you apply for a 1-year extension.
My bank requires a Certificate of Residence from immigration. Chiangmai immigration will send one through the mail in 7 days for 40 baht postage. There is no expedited service at the moment.