Pattaya and Krabi have flights from Dubai, and Samui from Singapore and Hong Kong.
As an American with a long history of EDU visas, I typically enter Thailand through Chiang Mai. I come in on Tourist and convert to EDU.
Are Pattaya, Krabi, and Samui low on immigration officer scrutiny like Chiang Mai? Or more like BKK, DMK and Phuket?