The TM 30 form is generally required for visa extensions in Thailand, though some immigration offices may not ask for it depending on the type of extension. It is advisable to have it on hand as it is a legal requirement.
Andy *******
Yes
Ben *****
Assuming you mean a regular 30 day extension for a tourist visa or visa exemption, Bangkok usually doesn't ask, but some immigration offices may want it. I think it's best to have one just in case and as someone mentioned before it is a legal requirement.
Stuart *********
What type of extension? A number of offices won’t ask for a tourist or exempt extension, but will for all others.
Jeremy ********
Only if you get one when you land…the last 3x I’ve been through bkk it wasn’t necessary for immigration at the airport..