Hi, I’m sure this has been asked many times, sorry. Wanting to go away for Christmas, extension due for 31 December , how long in advance can i apply for an extension ? And will Jomtien immigration be open on the 28/29th December ?(Thanks. I entered on visa exempt. I will be leaving Thailand on the 21 st of January and doing a tourist visa in Penang to come back in for 6  Weeks )

You can do it a week early without problem.

After next Monday the 11th their are no more holidays this year. The holidays for New Years are the 1st and 2nd of January.