I have both US and UK passports. Flying BKK-DOH-DXB with an overnight in Doha where I plan to enter Qatar. Am I best served by checking in with my UK passport at BKK so that there’s no fee in Doha? Even if I enter Thailand on my US passport?
That's an interesting question, I am pretty sure that you have to use same one that you entered with, when you are exiting at the immigration. But in theory you can check in with another one. I don't know if immigration officer would see this or make fuss about it. Would be interesting to hear if someone knows for sure.