What should I do if my landlord can't register my address before applying for a visa extension?

You're asking to do the TM30. Follow Robert's advice. The owner will have to add information about his bluebook (he'll know what that is), his ID number, and related information.

If he needs more information on how to set this up, he can follow the step-by-step instructions in the manual, found by clicking on the button that says "คู่มือแจ้งที่พัก User Manual v.4" on Robert's link.

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I did this on Friday in Phuket immigration. Yes, you need copy of your rental contract, copy of your passport, and paperwork from landlord: notification from house master, owner or the posessor of the residence and most likely a power of attorney form if the registration hasnt been done online.

Are you referring to TM30? Some immigration offices you can do this by mail.

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