You need to talk to a vet in your home country to get the Fit to Fly certificate and any authorizations there. You also need to talk to Thailand and can only board a flight with an import certificate. Email they helped us for 4000thb. It takes a few days... if you have that. All vaccines. And the health certificate from country you are leaving. Plus any authorizations. You can fly. On arrival... you need can't walk out... you need to go to VET LIVESTOCK OFFICE next to luggage with your pet. Pay. Show documents. Show the microchip is the same as the import permit. Then go to CUSTOMS and show cat. Pay tax. Then keep that receipt. Any time pet reenters no need to pay tax in Thailand again. That's it.