@Ashley ********
>Can the extension be done at any immigration office in Thailand?
The 30 day extension of stay based on tourism can only be acquired at the immigration office where the TM30 is filed (the TM30 is submitted automatically by the hotel you're staying).
To get this extension of stay, you will require
1. Your passport and a copy of:
a. The data “picture” page.
b. The most recent visa (if applicable).
c. The most recent entry stamp or extension of stay (if applicable).
d. The departure card (“TM 6”) that should be stapled in the passport.
2. The extension of stay application form (“TM 7”).
3. 2x passport sized (4cm by 6cm) photos.
4. 1,900 THB processing fee.