Most dual citizens assume they can pick whichever passport suits them best. For most, that’s true, but for anyone holding a Canadian passport, the situation is more complicated. The rule is absolute: if you’re a Canadian citizen, you cannot apply for an eTA and must travel to Canada on your Canadian passport. For everyone else holding two passports, the question becomes which one to use, and that single choice, made carefully before you open the form, determines everything that follows. If a passport renewal happens mid-cycle, remember that a new passport number breaks the link to your existing eTA, so you’ll need to apply again on the new document. Travelling with a baby? A child who is a foreign national needs an eTA of their own.
So which passport should you use to apply for a Canada eTA if you hold two? If you’ve already submitted and want to track progress, the guide on checking your eTA application status covers that in detail. If one of them is Canadian, the eTA question is irrelevant: you don’t need one and you can’t get one. If neither is Canadian, use the passport from the visa-exempt country and apply with that one. The rest of this guide walks through what that actually means in practice.
The one rule that changes everything: if you’re a Canadian citizen
Canadian citizens, including dual citizens, must have a valid Canadian passport to fly to or transit through Canada by air. That’s not a preference or a recommendation—it’s the requirement. A valid Canadian passport is the only document that proves Canadian citizenship and the right to enter Canada without immigration screening.
The reason dual citizens get caught by this is that their second passport may be from a country whose citizens do need an eTA. It can seem logical to apply with that passport and skip the hassle of renewing a lapsed Canadian one. That logic fails at check-in. The airline is looking for either a Canadian passport or a valid eTA linked to a visa-exempt foreign passport—and if you present a non-Canadian passport with an eTA attached to it, a border officer can still ask why you didn’t travel on your Canadian document. Canadian citizenship carries an obligation to use the Canadian passport for entry, not just a right to do so.
There is one narrow exception worth knowing. If you hold a second passport from a visa-exempt country, you’re not American-Canadian, your flight departs in fewer than 10 days, and you’ve previously held Canadian citizenship documents, a special authorization to board may be available. This is a contingency, not a planning route. If your Canadian passport has lapsed and your trip is weeks away, the time to act is on the passport renewal, not on finding workarounds.
The Canadian-American case runs slightly differently. Canadian-American dual citizens can fly to Canada with either a valid U.S. passport or a valid Canadian passport—but if they travel on the U.S. passport alone, they must carry identification that shows their Canadian citizenship. U.S. citizens are also entirely exempt from the eTA requirement, so a Canadian-American travelling on a valid U.S. passport doesn’t need an eTA at all, just that supporting proof of citizenship.
If neither of your passports is Canadian: the one choice that matters
Once you’ve confirmed that neither passport is Canadian, the decision comes down to which country’s passport is from a visa-exempt country. The eTA exists for visa-exempt foreign nationals travelling to Canada by air—if your passport isn’t from a visa-exempt country, you’re not eligible for an eTA through that document regardless of your other citizenship.
In most dual-citizen situations where someone is asking this question, one passport is from a visa-exempt country and one is not. The answer is immediate: apply with the visa-exempt one. If both passports happen to be from visa-exempt countries, choose the one you’ll actually be travelling with—the one you’ll hand to the airline at check-in and to the border officer on arrival. That matters because the eTA is electronically linked to the specific passport used for the application, and you must present that same passport when checking in for your flight.
Practically, this means the passport you apply with is the passport you travel with. Pick the one that’s valid for the duration of your trip and that you’re confident you’ll have in hand at the airport. An eTA is valid for up to five years or until the passport it’s linked to expires, whichever comes first — see how long a Canada eTA is actually valid for how that plays out — so if one of your passports expires sooner, factor that into which one you choose, especially if you plan to return to Canada more than once.
One scenario that trips people up: applying with one passport because it’s the one they happened to have nearby, then packing the other for the trip. The check-in agent scans your passport and the system looks for an eTA linked to that document. If the numbers don’t match, you’re not boarding.
The one detail that stops most dual-citizen rejections
The passport number you enter on the eTA application must exactly match the number in your physical passport. Not approximately. Not close enough. Exactly. Entering the wrong passport number may prevent you from travelling to Canada—and the mismatch is discovered not when you apply, but when the airline scans your passport at check-in and finds no valid eTA attached to it.
The number to use is at the top of the information page—the page with your photo. For dual citizens, this is where mistakes cluster. When you’re juggling two passports, it’s easy to copy the number from the wrong document, or to type the number from the passport you’re holding while looking at the application for the other one. Before you submit the form, put your second passport away. Have only the one you’re travelling with in front of you. Read the number directly from the physical document, not from a scan or a photo on your phone, and check it character by character after you’ve entered it.
If you get a new passport after your eTA is approved—whether because the travel document expired, was renewed, or was replaced—you’ll need a new eTA. The approval is tied to the passport number, not to you as a person. This matters for dual citizens who might renew one passport mid-validity of an eTA linked to the other: the eTA linked to the renewed passport is no longer valid, even if the eTA itself hasn’t reached its five-year limit. The eTA approval and new passport situation is worth reading through if you’re in the middle of a renewal cycle.
What happens after approval—and why the eTA isn’t the final gate
Once you’ve applied with the right passport and the right number, most decisions come back within minutes. Some take several days if supporting documents are requested. When approval arrives, check the confirmation: the passport number in the approval email must match the number in your physical passport. That’s your last chance to catch a data-entry error before the airport.
At check-in, airline staff will scan your passport to confirm a valid eTA is attached to it. This is the moment the passport-matching rule becomes concrete—there’s no manual override available at the check-in desk. If the scan finds nothing, the conversation with the agent is not a productive one.
What the eTA does not do is guarantee entry into Canada. A valid eTA and a valid travel document get you on the plane; a border services officer makes the final decision on whether you meet all entry requirements when you arrive. For most travellers this is a formality, but dual citizens sometimes face additional questions—particularly if the officer is aware of a Canadian citizenship connection. Carrying any documentation that clarifies your citizenship situation clearly and honestly is worth doing, even if it’s not required.
If an application comes back refused rather than approved, the path forward depends on why—what happens after a Canada eTA refusal covers the options and the timing considerations in detail. The short version: a refusal on one passport doesn’t automatically mean a refusal on the other, if the second passport is also from a visa-exempt country and the refusal was tied to specific information entered on the first application.