My wife is a Thai who recently became a Canadian citizen. We are travelling to Thailand for 10 weeks this coming November and my wife will have a Canadian passport by then. Exactly how should we be using the passports as far as leaving and entering the respective countries? I am thinking that a Thai passport would be used to leave Canada and enter Thailand. Then both passports would be need to be shown when leaving Thailand to close off the Thai travel loop, and then entering Canada on Canadian passport? Would this be best practice? TYIA
-Important thing is that if you are entering a country in which you have citizenship, you generally MUST present passport of that country (some countries are more strict than others about this). They may ask about other citizenships, that's your problem.
-If you entered a country under one passport, use that same passport to 'exit' (i.e. to show at passport control/customs when leaving). Note that Canada does not have this type of exit control, so there's no-one to 'show' your passport to when leaving (except to airlines).
-The rest is the airlines: they always want to see that you have ability to enter the country you're flying to (because they get in $$$ trouble if they bring passengers to a country that are not allowed). They generally don't care which passport you used to book the ticket. In some cases, they may require you to enter passport info of the passport you need to enter a country into their system; depends on the airline.
So in your spouse's case:
-Thai passport to enter and exit Thailand.
-Canadian passport to enter Canada.
-Show the airlines passports as necessary.
[Side note: for countries that issue electronic travel authorizations or similar, the system may or may not allow a dual citizen to get an ETA. That doesn't absolve you of responsibility to enter under your national passport if required by law. Same thing for no-visa required cases.
