SSN or ITIN: Tax Numbers for New U.S. Residents
Who gets an SSN, who needs an ITIN, when each is needed, and switching between them
Reviewed by the Fairlight Accounting cross-border tax team — U.S. & Canadian Tax Desks
New U.S. residents need a taxpayer identification number. Canadians authorized to work — TN, L-1, H-1B, and E-2 holders, and green card holders — get a Social Security number. Family members who can't work, such as some dependent spouses and children, need an ITIN, applied for on Form W-7 with a return. A later SSN replaces the ITIN.
On this page
Who gets which
| Person | Number |
|---|---|
| Green card holder | Social Security number |
| Work-authorized visa holder (TN, L-1, H-1B, E-2 principal) | Social Security number |
| Dependent spouse with work authorization (E-2 and L-2 spouses, whose I-94 shows E-2S or L-2S; H-4 spouses with an EAD) | Social Security number |
| Dependent spouse or child without work authorization (TD dependants, for example) | ITIN, applied for with a return (the ITIN guide) |
| Canadian with only U.S. rental income or a property sale | ITIN |
Timing
Work-visa holders (TN, L-1, H-1B, E-2) apply after arrival — start online, then visit a Social Security office with their passport and immigration documents. Immigrant-visa holders can request an SSN on the DS-260 visa application (Enumeration at Entry), with the card mailed within about 7 to 10 business days of arrival; green card applicants adjusting status in the U.S. can request one on Form I-485 (Enumeration Beyond Entry). An ITIN is requested with the first return that needs it. Under P.L. 119-21, the child tax credit (up to US$2,200 per child for 2026) requires a work-valid SSN issued by the return's due date for the child and for the taxpayer (or at least one spouse on a joint return); a child with only an ITIN can qualify only for the US$500 credit for other dependents (the Canada child benefit guide).
Switching
Someone who gets an SSN after using an ITIN writes to the IRS asking that their tax records be combined; the IRS then voids the ITIN and associates all prior filings with the SSN.
Frequently asked questions
Do I need a Social Security number as a TN worker?
Yes — work-authorized visa holders get an SSN.
What does my non-working spouse need?
An ITIN, unless their status allows work and an SSN.
Can I claim the child tax credit with an ITIN for my child?
No — the child needs a work-valid Social Security number, and since 2025 so do you (or your spouse on a joint return); a child with an ITIN may qualify for the US$500 credit for other dependents.
What happens to my ITIN when I get an SSN?
You notify the IRS, the records are combined, and you stop using the ITIN.
Official sources
The Social Security Administration explains: “In general, only noncitizens with permission to work from the Department of Homeland Security can get a Social Security number.” — Social Security Administration, If I am not a U.S. citizen, can I get a Social Security number?, https://www.ssa.gov/faqs/en/questions/KA-02178.html
The IRS explains: “An ITIN is a 9-digit number the IRS issues if you need a U.S. taxpayer identification number for federal tax purposes, but you aren’t eligible for a Social Security number (SSN).” — Internal Revenue Service, Individual taxpayer identification number (ITIN), https://www.irs.gov/tin/itin/individual-taxpayer-identification-number-itin
Next step
Fairlight Accounting is a cross-border accounting and tax practice with a U.S. Tax Desk and a Canadian Tax Desk. Our U.S. Tax Desk and Canadian Tax Desk handle taxpayer number planning for new U.S. residents and their families, ITIN applications, and first-year returns. See pricing or book a call.
Cross-border taxes, handled in one place
U.S. and Canadian filings prepared together by our U.S. and Canadian Tax Desks.
Book a free fit call