Did you enter the details of you Canadian passport during the check-in process? Gate agents will generally insist on seeing the same document entered / presented during check-in.

Countries like the U.S. and Canada and such don't tell other governments about a person if he acquires citizenship from them and the home country doesn't usually know unless it's someone famous.

Since you have Malaysian and Canadian citizenship, here's what you do (this is all assuming you didn't get Canadian citizenship through asylum or anything and that your name is the same on both Canadian and Malaysian passports):

Canada to Malaysia

Don't bother yourself with multiple airlines if you don't have to. In Canada, book a ticket to Malaysia via Cathay Pacific, let's say, and use your Malaysian passport information.

When you check in, show the airline your Malaysian passport.

When you go through security to enter your terminal, show your Malaysian passport and boarding pass. Canada doesn't do exit stamps or checks on your status.

When you board the plane, show the gate airline agent your Malaysian passport.

Do the same in Hong Kong when you board your flight to Malaysia.

When entering Malaysia and going through immigration, show your Malaysian passport.

Malaysia to Canada

This will work a little differently.

When checking in at the airline in the Malaysian airport, show them your Malaysian passport (since it's the one that has the passport info) and show them your Canadian passport because it's proof that you're able to enter Canada.

When going through Malay exit immigration to enter the terminal, show them your Malay passport. Do NOT show them your Canadian passport as it's none of their business. All they're concerned about knowing your legal status in Malaysia.

When boarding the plane, show the airline gate agent your Canadian passport.

From Hong Kong and after, continue using your Canadian passport until you arrive in Canada, where you'll also show your Canadian passport.

It might be a little different if your name is different or differently spelled on both passports or if you're an asylee. Either way, you don't have to buy separate tickets, though you can if you want to be extra cautious, though it might stand to complicate things.

That is a fairly naive stance. Of course no Canadian official is going to call his Malaysian counterpart to tell on someone (though it could happen). Think a bit more laterally; when you renew your Malaysian passport you will have to answer the question of whether you have acquired another citizenship, or whether you are a citizen of another country. Sure, you could lie, but that has consequences. What if you get stopped at Malaysian immigration next time you enter the country and are asked, or indeed searched? There are many permutations of these scenarios.

I have not read the Malaysian immigration act, but I'll bet that the act of acquiring Canadian citizenship automatically revokes Malaysian citizenship. That the person still holds a passport (which, by definition, is at that point invalid), is an anecdote.

The OP needs to answer whether he's asked by authorities if he acquired another citizenship whenever he renews his passport. I don't know about Malaysia, but I don't know if that's a question normally asked by other countries (mine doesn't allow dual citizenship but they don't ask about it when renewing my passport). Of course there's always a chance he might be stopped and asked, but generally speaking immigration and authorities in many of these nations will not bother with you unless you're someone who made a stink. But if he's no one who's well-known or an asylee, his chances of being scrutinized are extremely slim. A lot of the time they're just too lazy to be bothered in practice.

Nope, it was my UK details on the API.

Huh, so I guess airlines these days are super-cautious? It seems that your return ticket made them to check your entry eligibility into Canada, though technically they could just leave it to the people at UK airport that's going to check-in your return flight to Canada.

Another unlikely reason is that airline check-in counters somewhat double/help with CBSA (canadian border service agency) in monitoring border exit.

How do you check which passport is on the API btw?

Thanks, I was thinking about that. But then all these "rumors" about AC asking to see your proof of Canada residency (e.g. PR card, visa, passport) at check-in departure from Canada and AC sending API data (include passport) to country of destination make me unsure about your method above.

It seems using a proxy third country is the safest bet.

The API is whatever you fill in (i.e. I pick which of my passports I put in) unless your airline retains the information for you from past trips. From this single experience it is hard to say what the motivation was, but I suspect absolutely nothing to do with CBSA, as nothing was done with the information (literally, they looked at the data page of the passport at the beginning of the jet bridge, then let me board), but they were also looking at non Canadian's PR cards as well, so it had to be something to do with getting back to Canada, that's the only reason I can think of. But in your situation, whichever one you leave Canada on, you would have the other one with you in any case so wouldn't be an issue if this happened (and as I mentioned, this has only happened once).

Yeah, I'm pretty certain Air Canada will not ask you about proof of residence if you're leaving Canada. That's not the job of the airlines and their only job is to make sure you have a visa, PR card, citizenship, whatever allows you into your destination country. The only time AC is going to ask about documents allowing you into Canada is when you're checking into a flight headed to Canada. And even if some weird anomaly like emma69's case happens, Malaysia isn't a country that demands API as far as the lists I've seen.

What I know is that only certain countries demand API and Malaysia isn't one of them. Malaysian authorities likely will not demand anything aside from seeing your Malaysian passport. If you book separate tickets and tell them you were in a third country this whole time, it stands to complicate things further.

A lot of this has to do with knowing people who have done similar extensive travel. Many of my friends are Saudi-Americans, and they book flights from the US to Saudi via a European airline and they use their Saudi passport info (mind you Saudi isn't a country that demands API edit: it's possible that Saudi demands API). Despite the API, U.S. authorities never asked them about their Saudi passports presumably on the API system whenever they landed in the States. They just show the proper passports at the proper times and they've been doing this for 20+ years. I imagine it's similar in Malaysia.

Either that, or if you want to play it extra safe, fly into Singapore and enter Singapore using your Malaysian passport then get into Malaysia by land.

It might not make much of a difference if you book your ticket on either passport as long as you know which passports to present, but if you want to play it safe with Malaysian authorities, book it using your Malaysian passport.

Bottomline is: it's not that complicated so I don't advise you to complicate things with separate flights and separate legs of flights, and it'll go well.

Thanks! I manage to dig some information on countries with API and found this:

Presentation - Passenger Data Toolkit

The data is from September 2013, and it seems that Saudi Arabia does require API, while Malaysia does not at that time.

This article seems to detail the legal position: https://www.thestar.com.my/news/nati...-holders-told/

Otherwise most of the posts in this thread are along the right lines - people operate under a don't ask don't tell policy,

Theoretically someone could analyse your passport stamps, but think about the average day in the life of a low-level government employee processing passport renewals, who can be bothered unless there is a specific directive or reward from higher up?

I know several Malaysians living in Australia who have become citizens but still keep and renew their Malaysian passports, but they go back to Malaysia frequently.

I have heard of spot checks by Imigresen at boarding gates in KUL - here you need to show your non-Malaysian passport! (This is just a visual check from what I have heard)

China (PRC) is a different case - if a government official discovers you have multiple passports, even by accident, they will force you to make a decision on the spot.

Interesting. Although, if you had say a UK and Chinese passport, and you told them 'I want to keep the Chinese one' and they 'remove' your UK passport, you're still a UK citizen. Unless they just revoke the Chinese citizenship on the spot, which would work.