Do all 60-day COVID extension processes occur at Chaengwattana or Muang Thong Thani?

IF you entered the country on a visa exempt entry <- meaning you didn't BUY a tourist visa from a thai consulate before you came here, you use MTT counter K and you need to make an appointment to go

IF you entered the country on a real tourist VISA <- meaning you DID buy a tourist visa from a thai consulate before you came here and were stamped in for 60 days you go to Counter J and while it is suggested you make an appointment, it is not necessary and you can walk in

MTT counter K

If you've been here since the lock down last March

@J**

what stamp did you originally enter the country on?

Whether you use Chaengwattana OR Muang Thong Thani to get a covid extension is controlled on what entry stamp you came in on.