What is the process and experience for extending a MMT Visa in Thailand?

Thanks Alexander Cheberk for the MMT VISA extension summary!

Points learned today vs other sources, etc

Only 1 copy of the documents.

TM30 not required.

Printed out USA embassy letter was ok. Got the embassy letter next day at 8:10AM.

Nobody asked for the online appointment doc.

Form STM2 - they asked me to redo it and complete it in front of them, 2nd floor.

GPS - I drove and parked at the roundabout. Possible parking in the back but the front gate was closed.

Temporary VISA Extension Center at Muang Thong Tani

Ban Mai, Pak Kret District, Nonthaburi 11120

[members only]

Got there at 1315 to the small exterior tent.

Confusion... just sit in a chair and wait.

Called up to the 3rd floor parking garage, highly suggest sitting on the far right row of seats, 5 rows 20 deep. I sat in the 4th and it took an hour before moving to the 2nd floor.

When leaving the 3rd floor, all 5 rows full again.

2nd floor took an hour, checked documents, got a number, 600ish.

1st floor - zero questions asked. Took my 1900B. Went to another queue and waited for the passport.

3 hours total.

Rain smashed down and 3hr return trip.

No taxi cars waiting when I exited but they were there when I arrived.

Would suggest showing up closer to 3 or early and sit in the right side row.

Sept 23 with Oct 21 stamp.

Told I could come back for renewal.