Canada and US Dual Citizenship: What Americans Need to Know

Bill C-3 came into force on December 15, 2025 and removed the first-generation limit, the rule that had cut citizenship by descent off at the first generation born outside Canada. Many people who were correctly refused under the old rule are applying again.

When a claim by descent holds up, you are already a Canadian citizen by operation of law. The application does not make you Canadian. It simply asks Immigration, Refugees and Citizenship Canada to confirm something that is already true.

If you are not sure where your family line stands, check IRCC’s documentation for whether you may already be a citizen.

Which of These Are You? The Two Paths

Almost everyone reading this falls into one of two groups, each of which involves different applications under different sections of the Citizenship Act.

Path A: you have a Canadian-born or naturalized-in-Canada ancestor.

Your application is a proof-of-citizenship application under section 3 of the Act, and you are applying to IRCC for a citizenship certificate.

This path confirms a status you already hold. There is no residency requirement, no oath, no ceremony, and no medical or background screening that comes with immigrating.

The bulk of this process is documentation: proving that each generation in your line connects to the next, and that no older rule breaks the chain. Our guide to claiming Canadian citizenship by descent covers how to build that proof.

Path B: you have no Canadian ancestry.

For an adult with no Canadian parent, there is no direct route to citizenship.

You become a permanent resident first, through economic immigration, family sponsorship, or a work permit that leads to permanent residence. Then, you apply for a grant of citizenship under section 5.

The residency requirement for a grant is 1,095 days of physical presence in Canada within the five years before you apply. Days held as a permanent resident count in full, and time spent in Canada before you had permanent-resident status counts as half a day, to a maximum of 365 days.

The honest emphasis on Path B is the opposite of what most people expect: the difficult part is actually becoming a permanent resident, and citizenship afterward is comparatively straightforward.

If that is your situation, the useful reading is our overview of how Americans can immigrate to Canada.

Do the US and Canada Both Allow Dual Citizenship?

Yes, both countries allow dual citizenship.

Canada has permitted multiple citizenship since 1977 and does not require you to give up any other nationality. In the US, the State Department expressly recognizes dual nationality. It also notes that dual nationals owe allegiance to both countries and must obey the laws of both.

Will Becoming Canadian Cost Me My US Citizenship?

For the overwhelming majority of readers, the answer is “no”.

However, there are a few key concepts you should know to understand the deeper complexity at work.

Loss requires intent, not merely the act.

Under US law, naturalizing in a foreign state or taking an oath of allegiance to one results in the loss of US nationality only when done voluntarily and with the intention of relinquishing US nationality.

The State Department's administrative presumption runs the other way: a US citizen who naturalizes abroad or swears a foreign oath is presumed to intend to keep US citizenship.

The protection is the intent requirement, not immunity. Someone who tells a consular officer that they mean to give up US citizenship can and will lose it.

Most people claiming by descent never take an oath at all.

A section 3 proof application confirms an existing status. There is no ceremony and no oath of allegiance. Only section 5 grant applicants swear one. Readers routinely assume a ceremony is coming, and on Path A it is not.

The renunciation language in a historic US naturalization oath does not renounce Canadian citizenship.

People get this backwards constantly. The wording in older US oaths about renouncing allegiance to foreign sovereigns does not, on its own, end a Canadian claim, and acquiring US citizenship is not the same thing as formally renouncing Canadian citizenship.

Formal renunciation to Canada is a separate, deliberate application, and it is rare.

Before 1977, a Canadian who voluntarily naturalized in another country generally did lose Canadian citizenship, and successive amendments to the Citizenship Act, most recently Bill C-3, have restored most of those lines.

Our Lost Canadians explainer covers those categories. Where dates fall close to those older rules, the line needs a legal review rather than an assumption in either direction.

Which Passport Do I Use at the Border?

Carry both.

Enter and leave the United States on your US passport. When flying into Canada, either passport works for a Canada-US dual citizen, but bring your Canadian citizenship certificate as well.

The general Canadian rule is that dual citizens cannot fly to Canada on a foreign passport, because Canadian citizens are not eligible for an electronic travel authorization and so cannot be boarded on that basis.

However, there is an express carve-out: Canada-US dual citizens may fly to Canada on a valid US passport. IRCC advises carrying evidence of Canadian citizenship when you do so, which, in practice, means the citizenship certificate.

When entering the United States, the State Department position is clear: a US citizen must enter and leave on a US passport. At land and sea ports of entry, the Western Hemisphere Travel Initiative also accepts a passport card, an enhanced driver's license, or a NEXUS, SENTRI, or FAST card. However, none of those are accepted for air travel.

What Canadian Citizenship Actually Gets You (and What It Doesn't)

Canadian citizenship gives you a specific set of rights, but it leaves many assumptions untouched.

What You Gain

• The right to live and work anywhere in Canada, with no employer tie. This matters most to anyone on a work permit, which is linked to a specific employer. A citizen needs no authorization at all and is tied to no one.
• Domestic tuition. This comes up in more consultations than any other item on this list. Canadian universities price in tiers: in-province residents, then Canadian citizens and permanent residents generally, then international students. International rates are often double or triple domestic tuition.
• Buying property without the foreign-buyer taxes. Ontario's non-resident speculation tax is 25 percent of the purchase price, and British Columbia has its own foreign buyer and speculation taxes. A Canadian citizen is not subject to them.
• The vote, and the right to run for office.
• A Canadian passport and Canadian consular protection when you travel.
• The ability to pass citizenship to your children, within the descent rules, which changed when Bill C-3 removed the first-generation limit and, for births on or after December 15, 2025, include the substantial connection test noted earlier.

What You Do Not Gain

• Healthcare is not unlocked by citizenship. This is the most common assumption. Provincial health coverage follows residency, and each province sets its own waiting period.
• Your children are not automatically documented. Each child needs their own application, and for births on or after December 15, 2025, the question is not just documentation but whether the child is a citizen at all. Where a child has only a passport, our note on identity documents for a child's citizenship certificate covers what IRCC will accept.
• It does nothing for your spouse. This surprises almost every client. A spouse without their own Canadian line goes through spousal sponsorship, a separate and considerably heavier process than confirming your own citizenship.
• The certificate is not a passport. It is a document confirming that you are a Canadian citizen. The passport is a separate application to a different office.

Tax: What Changes & What Doesn't

Canada taxes on residence, not citizenship. Becoming a Canadian citizen does not, by itself, put you into the Canadian tax system.

If you later move to Canada, own property there, or run a business there, Canadian tax residence becomes a real question, and the Canada Revenue Agency's guidance for newcomers is the starting point.

The United States works the opposite way. The US taxes its citizens on worldwide income regardless of where they live, so an American continues to file US returns after becoming Canadian.

However, this obligation attaches to the US citizenship you already hold. The Canadian claim does not create it. This means that confirming Canadian citizenship does not create a new US tax problem for you.

Filing is also not the same as owing. Foreign tax credits and the Canada-US tax treaty generally prevent the same ordinary employment income being taxed twice. For most people, the burden is administrative more often than it is financial.

For US taxes, one reassurance at a high level: becoming a Canadian citizen does not by itself create a Canadian tax liability. Canadian tax generally follows residence, not citizenship, and the Canada-US treaty addresses double taxation. This is general information, not tax advice; speak with a cross-border tax professional about your situation.

Ask a cross-border accountant about:

• FBAR and FATCA reporting on foreign financial accounts.
• The Canada-US tax treaty and foreign tax credits (include this one; it is the reassurance).
• TFSA, RESP and RDSP.
• PFIC exposure on Canadian mutual funds and ETFs.

Marin immigration has a CPA referral, contact us to connect.

Renouncing US Citizenship

Some Americans living in Canada eventually consider giving up US citizenship.

That is a United States process, handled by the State Department, with its own tax consequences under US expatriation rules (Form 8854 and the exit tax).

It is outside our practice, and we do not advise on it. Speak with US counsel and a cross-border accountant.

Practical First Steps

Step 1. Look for a Canadian Ancestor in Your Direct Line

Work backward one generation at a time and ask whether anyone in your direct line was born in Canada. The cheapest useful move is a few hours of your own time on FamilySearch or Ancestry, looking for the birth, marriage, and death records that connect each generation. You can often confirm or rule out the basic shape of a claim before spending real money on it.

Step 2. Order Records & Read the Guide

Order your own long-form birth certificate and your parent’s, then read IRCC's official guide for the proof of citizenship application, CIT 0001 directly, rather than blog posts. Their guide is the single source of truth on what IRCC requires, and the application fee is CAD $75.

Where Files Run into Trouble

Issues typically arise when there is a missing primary record, a document without a citation linking it to the authority that created it, or a conflict between two records left unresolved.

Our write-up on Lessons Learned From Recent Files sets out what a complete package looks like.

If There Is No Canadian Ancestor

Your first step is an eligibility check for economic immigration, not a citizenship application. Those are different systems with different criteria, and starting in the wrong one costs you months.

If you would like a lawyer to look at your family line before you commit to an application, you can book a consultation with Cédric Marin.

Frequently Asked Questions

Do I lose my US citizenship if I become Canadian?

Almost certainly not. Under US law, loss of nationality through foreign naturalization or a foreign oath requires that the act be voluntary and done with the intention of relinquishing US citizenship. The State Department presumes that you intend to keep it. If you are claiming Canadian citizenship by descent, there is no oath or ceremony involved at all.

Do Canadian citizens have to pay US taxes?

A Canadian citizen who is not a US citizen or US resident generally has no US filing obligation. If you are a US citizen, you continue to file US returns regardless of where you live, because the US taxes citizens on worldwide income. That obligation comes from your US citizenship, not from becoming Canadian.

Does becoming a Canadian citizen affect my US taxes?

Not by itself. Your US filing obligations come from being a US citizen, which you already are. What can change your tax picture is moving to Canada, earning income there, or acquiring Canadian assets, all of which are questions for a cross-border tax professional.

Which passport do I use when I travel between Canada and the US?

Enter and leave the United States on your US passport. Flying into Canada, a Canada-US dual citizen may use a valid US passport, and should carry a Canadian citizenship certificate as evidence. Arriving by land or water, a citizenship certificate with photo ID is also acceptable.

Do dual citizens get healthcare in Canada?

Not automatically. Provincial health insurance follows residency, not citizenship, and each province sets its own eligibility rules and waiting periods. Holding Canadian citizenship while living in the United States does not enroll you in any provincial plan.

Can I pass my Canadian citizenship to my children?

Often yes, and each child needs their own application. For children born outside Canada before December 15, 2025, the line generally passes down to the point where the chain can be proven. For children born outside Canada on or after that date, citizenship depends on the substantial connection test, which looks at the parent's physical presence in Canada before the birth.

Can a US citizen work in Canada without a permit once they are a citizen?

Yes. A Canadian citizen does not need a work permit and is not tied to a particular employer. Until citizenship is confirmed, a US citizen needs authorization to work in Canada, which is one of the practical reasons people pursue a certificate.

This article is general information, current as of its publication date, and is not legal or tax advice for your specific situation. Immigration and tax rules change. Speak with a qualified professional about your own circumstances.

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