Snowbird Tax Rules: How to Avoid Accidental U.S. Tax Residency

UPDATE (August 14, 2026): This article has been updated to reflect current IRS guidance and filing considerations since the original date of publication (March 16, 2018).

If you’re a Canadian who spends part of the year in the U.S., keeping track of your travel days is more than a good habit. It can help you avoid accidentally becoming a U.S. resident for tax purposes.

Many Canadian snowbirds assume U.S. tax residency only becomes an issue if they spend more than half the year south of the border. In reality, the IRS uses a weighted three-year calculation called the substantial presence test. That means regular winter travel, even for less than six months at a time, can still create U.S. tax filing issues if you’re not paying attention.

How the substantial presence test works

You may be considered a U.S. resident for tax purposes if you are physically present in the U.S. for at least:

• 31 days during the current year, and
• 183 days over a three-year period that includes the current year and the two previous years.

The 183-day total is calculated by counting:

• All days you were present in the U.S. during the current year;
• One-third of the days you were present in the previous year; and
• One-sixth of the days you were present in the second previous year.

For example, if you spend 120 days in the U.S. each year, your weighted total would be 180 days: 120 days from the current year, 40 days from the previous year, and 20 days from the second previous year. In that example, you would not meet the substantial presence test.

However, increasing your annual time in the U.S. by even a few days can change the result. That’s why it’s important to track your days carefully, especially if you regularly spend three to five months in the U.S. each year.

What counts as a day in the U.S.?

In general, any day you are physically present in the U.S. counts as a U.S. day, even if you were only there for part of the day.

There are some exceptions. For example, certain days spent in transit for less than 24 hours between two places outside the U.S. may not count. Days may also be excluded in limited circumstances where you were unable to leave the U.S. because of a medical condition that arose while you were there.

Because the rules can be specific, don’t rely on estimates or memory. Keep a travel log that records each date you enter and leave the U.S., and retain supporting information such as flight records, passport stamps, credit card statements, and other travel documents. CBP travel history can be a helpful reference point, but it should not be treated as your only record.

The closer connection exception

Even if you meet the substantial presence test, you may still be treated as a nonresident of the U.S. if you qualify for the closer connection exception.

To qualify, you generally need to show that you:

• Were present in the U.S. for fewer than 183 days during the current year;
• Maintained a tax home in Canada during the year;
• Had a closer connection to Canada than to the U.S.; and
• Did not take steps toward becoming a U.S. lawful permanent resident.

The IRS looks at several factors when determining whether you have a closer connection to Canada, including where your permanent home, family, personal belongings, driver’s licence, business activities, social ties, and charitable affiliations are located.

For many Canadian snowbirds, these factors may still point strongly to Canada. However, spending extended time in the U.S., owning U.S. property, opening U.S. accounts, earning U.S.-source income, or moving more of your personal and financial life south of the border can complicate the analysis.

Don’t forget Form 8840

If you are relying on the closer connection exception, you must file Form 8840, Closer Connection Exception Statement for Aliens, with the IRS.

If you are filing a U.S. tax return, Form 8840 is attached to that return. If you are not required to file a U.S. tax return, Form 8840 is still filed separately by the applicable Form 1040-NR due date.

This deadline may be April 15 or June 15, depending on your circumstances. For example, nonresident aliens with wages subject to U.S. income tax withholding generally have an April 15 filing deadline, while those without wages subject to withholding may generally have a June 15 deadline. If the due date falls on a weekend or legal holiday, the deadline may move to the next business day.

Failing to file Form 8840 on time can mean losing access to the closer connection exception, unless you can show that you took reasonable steps to understand and comply with the filing requirement.

What if you are a resident of both countries?

In some cases, a Canadian snowbird may be considered a tax resident of both Canada and the U.S. under each country’s domestic tax rules. When this happens, the Canada-U.S. tax treaty may help determine which country has the stronger claim to residency for treaty purposes.

This is often referred to as using the treaty “tie-breaker” rules. However, relying on a treaty position may create additional U.S. filing requirements, including disclosure of the treaty-based position. It can also have Canadian tax implications, so it should not be handled casually.

Canadian tax residency still matters

Spending time in the U.S. does not automatically mean you stop being a Canadian tax resident. The CRA looks at your residential ties to Canada and the facts of your situation, including where you maintain a home, family connections, personal property, financial accounts, and other ties.

For many snowbirds, the goal is not to become non-resident of Canada. It’s to remain clearly resident in Canada while avoiding unintended U.S. tax residency or filing complications.

How to stay onside

If you spend significant time in the U.S., consider taking these steps before each travel season:

• Track every U.S. travel day, including partial days.
• Review your three-year substantial presence calculation.
• Keep documentation that supports your Canadian residential ties.
• File Form 8840 on time if you are relying on the closer connection exception.
• Get advice before extending your stay, buying U.S. property, earning U.S.-source income, or changing your immigration status.

Cross-border tax rules can become complex quickly, especially when retirement, investment income, real estate, or business ownership are involved. If you regularly spend time in the U.S. and want to understand how these rules apply to you, contact your DMCL advisor for guidance tailored to your situation.