If I'm ticketed through to Phuket but have to change planes in BKK, do I go through immigration in BKK or Phuket?

@David ******

hindsight is

Ok I decided not to risk it and bought a cheap ticket from Phuket to Penang return for thirty day after my arrival. Ill try to get a proper tourist visa in Penang. Hopefully they won't make me show too much forward travel from there, although I suppose I could buy a ticket from Thailand to say Laos or Cambodia for three months later (two month tourist visa plus and extension). Ha ha - at this rate it might have been cheaper for me to buy a return ticket in the fist place, and if needs be ditch the return portion. lol Oh well, ces't la vie!

Because I'm not sure how long ill be there or where I'm going next.

I had a small hassle once with that, and they just made me sign a waiver that I would not blame the airline if I was refused entry.

Flying in from Rome on an Canadian passport. Although I was thinking of using my Australian passport, which doesn't have a bunch of stamps in it...Better maybe?

But if they grant me thirty days, I should be able to get an extension of 30 on that, no?

I was married to a Thai man for about ten years from the early 80's, so at that time had no problem getting year long extensions. A bit different these days lol

Or if they hassle me could I just buy a ticket then and there at arrivals? Anyone done that or heard of it?

Thank you!