For people relocating from Mexico to the United States

Moving to the US From Mexico: Your First US Tax Year

Relocating from Mexico? The US decides tax residence by its own tests, your first year is usually split in two, and the US-Mexico treaty settles dual residence. Here is how each piece works.

Substantial presenceGreen card testDual-status yearTie-breakerSocial security

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Quick answer

When does someone moving from Mexico start paying US tax on worldwide income?

From the residency starting date: the first day in the US in a year you meet the substantial presence test, or the first day as a permanent resident under the green card test (IRS Pub 519). Before that you are a nonresident, so the first year is usually dual-status. If you are also resident in Mexico, Article 4 (Residence) of the treaty decides which country you are resident in for treaty purposes.

Prepared by Illuminous Accounting · Sources checked November 11, 2026

At a glance

When you become US resident: Green card test or substantial presence test (Code section 7701(b))
First year: Usually dual-status: nonresident, then resident
Treaty tie-breaker: Article 4 (Residence)
Social security agreement: None on the SSA list
Accounts in Mexico: FBAR, Form 8938 and PFIC rules can apply once resident

When someone from Mexico becomes a US tax resident

The US decides tax residence with two tests in Code section 7701(b), not by your visa label (IRS Pub 519). Arriving from Mexico, you become a US resident for tax purposes in a year if either applies:

Green card test: you are a lawful permanent resident at any time in the year.
Substantial presence test: at least 31 days in the US this year, and 183 days over three years counting all days this year, one third of last year's and one sixth of the year before.

Count your days with our substantial presence calculator.

The first US return after Mexico

The first US return after leaving Mexico is rarely a normal one.

Situation	What applies
Arrived mid-year and passed a test	Dual-status year: nonresident before the residency starting date, resident after it
Arrived late and passed neither test	Nonresident for the year, unless the first-year choice applies (31 consecutive days and 75% presence, plus the substantial presence test next year)
Married to someone still in Mexico	Special rules let some couples choose to file as residents for the whole year

Source: IRS Pub 519. See also first-year green card tax.

The treaty tie-breaker

Article 4 (Residence) of the treaty has the tie-breaker for someone resident in both countries: it looks first at where you have a permanent home available, then at the further tests the article lists, in the order it sets them.

Point	What it means
Who uses it	People resident in both Mexico and the US under each country's own rules, typically in the year of the move
How it is claimed	Form 8833 with the US return, under Treas. Reg. section 301.7701(b)-7 (IRS)
Risk for green card holders	Long-term residents may be treated as expatriated under section 877A

Accounts left in Mexico

Keeping a Mexican bank account or pension after the move is normal, but from your residency starting date the US wants to know about it. The reports are the FBAR, Form 8938 and, for many non-US funds, the PFIC rules on Form 8621 (IRS). Thresholds and deadlines: FBAR and FATCA, Form 8938.

Where these rules come from

Treaty

The IRS lists the 1992 income tax treaty, amended by a protocol listed for 2003. General effective date (IRS Table 3): treaty Jan. 1, 1994; protocol Oct. 26, 1995; protocol Jan. 1, 2004 (IRS treaty documents for Mexico; treaty text; IRS Table 3).
Residence and tie-breaker: Article 4 (Residence).
Article 19 (Pensions, Annuities, Alimony, and Child Support), pensions.
Article 24 (Relief From Double Taxation), relief from double taxation.
Article 15 (Dependent Personal Services), employment income.

US law

US residency tests and starting dates: Code section 7701(b) (IRS Pub 519).
Treaty residence for dual residents: Treas. Reg. section 301.7701(b)-7, Form 8833 and section 6114; long-term residents: section 877A (IRS Form 8833).
Social security agreements: SSA list.

The rules of Mexico on leaving the country also apply; check them with a local adviser.

How we help

Send us your arrival date, visa or green card dates and a summary of income and accounts in Mexico. We confirm your US status for the year, prepare the dual-status or resident return with the reporting it needs, and Gurleen Kaur, CPA licensed in British Columbia and Washington State, signs. Quote before any work.

Common questions

Am I a US tax resident in my first year after leaving Mexico?

When you meet the green card test or the substantial presence test (31 days this year and 183 weighted days over three years). Your residency starting date is generally your first day in the US that year, or your first day as a permanent resident.

What if I am resident in both Mexico and the US?

Article 4 (Residence) of the treaty breaks the tie, starting with where you have a permanent home. Claiming treaty residence in Mexico on a US return needs Form 8833.

Do I report my accounts in Mexico after moving to the US?

Once you are a US resident, yes: the FBAR when foreign accounts total more than US$10,000, Form 8938 above higher thresholds, and PFIC rules for many foreign funds.

Is there a US social security agreement with Mexico?

No, Mexico is not on the SSA list of agreement countries.

Sources

Every rule and figure on this page links to the IRS, CRA or other official source it comes from. Amounts change; we re-check them before each engagement.

Gurleen Kaur, CPA licensed in British Columbia and Washington State. Last updated November 11, 2026. This page is general information, not tax or legal advice for your situation.

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