I am visiting from the US and will be extended my TR Visa for 30 days. I understand that I will need to go to the Immigration office at Government Center Chaengwattana Building B, No. 120. I will need original passport, Visa, copies of both as well as a passport picture. Is that all or is there anything else? I read that I should wait until 3 days before my current Visa expires to do all this, is this true? Like if mine expires Monday the earliest I should go is Friday. Also is it still possible to make copies and get a passport photo done there?
TLDR : Answer Summary
To extend your TR Visa for 30 days in Thailand, you will need to prepare your original passport, the visa, copies of the passport data page, visa sticker, entry stamp, TM6 departure card, and a passport-sized photo. Additionally, a filled-out TM7 application form and 1900 baht are required. It is recommended to wait until 3 business days before your current visa expires to apply for the extension, meaning if your visa expires on a Monday, you should go no earlier than the previous Friday. You can also get passport photos and copies made at the immigration office.