Went to immigration in Pattaya last Friday to apply for a 30 day visa extension. I extended in March so thought I had all the required documents but nope. They wanted additional documents. So yesterday I went to the Bangkok office. The only documents I needed from my Pattaya package was the visa extension application, embassy letter, one copy of my passport and TM6 Thai entry/exit form. I also had to fill out a overstay penalty acknowledgement form (provided by immigration). I go back on Oct 5 for my new visa stamp that expires Oct 26.
TLDR : Answer Summary
This post discusses the experience of applying for a 30-day visa extension in Pattaya and subsequent documentation requirements when visiting the Bangkok immigration office. The user shares that, despite believing they had all necessary documents, additional documentation was requested in Pattaya. They detail the specific documents required for the Bangkok office, which included the visa extension application, an embassy letter, a copy of their passport, and the TM6 Thai entry/exit form, along with an overstay penalty acknowledgement form.