Form I-9 for TN workers: the documents, the 240-day extension, and why a new employer has to wait

A TN worker, a Canadian or Mexican professional admitted under the USMCA, completes Form I-9 like any other new hire: box 4 in Section 1 with the date their authorization ends, and usually a foreign passport plus Form I-94 as a List A combination in Section 2. Three TN rules shape the form as of November 2026: a timely extension your company files lets the worker keep working for up to 240 days; a new employer cannot put a TN worker to work until USCIS approves its petition or the worker is readmitted at the border, because TN has no filing-based portability; and a spouse in TD status may not work.

The H-1B version of these rules, including AC-21 transfers and cap-gap, is in Form I-9 for H-1B workers; the Supplement B mechanics are in I-9 reverification; and the recruiting side of TN, from eligibility to the support letter, is in TN visa hiring.

What does a TN worker enter in Section 1?

The worker checks box 4, "An alien authorized to work," and enters the date their employment authorization expires, which for a TN worker is generally the end date on their Form I-94. They also enter one of: an A-Number or USCIS number, the Form I-94 admission number, or a foreign passport number with the country of issuance. HR may explain the form but should not choose or correct the entries; see Form I-9 Section 1 instructions.

TN status is employment authorized incident to status under 8 CFR 274a.12(b)(19), for business activities at a professional level under Chapter 16 of the USMCA. A TN worker does not need an EAD, and asking for one would be asking for a specific document.

Which documents can a TN worker present?

• The usual choice, List A: an unexpired foreign passport with a Form I-94 bearing the same name and an unexpired endorsement of the status, as long as the job does not conflict with any restriction on the form (M-274 13.1). Record the passport in the first List A area and the I-94, with its end date, in the second. USCIS notes that employees generally download their I-94 from CBP's website.
• An option many forms miss, List B plus List C: M-274 13.3 lists, as an example of a DHS-issued List C document, a "Form I-94 Arrival/Departure Record issued to ... work-authorized nonimmigrants." A TN worker may therefore present a List B document, such as a state driver's license or a driver's license issued by a Canadian government authority, with the I-94 as the List C document.
• Not a List C document: a Social Security card marked "VALID FOR WORK ONLY WITH DHS AUTHORIZATION" (M-274 13.3).

The worker chooses. You can tell them what the lists contain, but even though your company drafted the TN support letter, do not ask for the passport and I-94 by name. If you use E-Verify, any List B document must have a photo.

How does the 240-day extension work on Form I-9?

A TN admission lasts up to three years, and extensions are granted in periods of up to three years with no fixed total limit (8 CFR 214.6(e) and (h)). There are two ways to extend: your company files Form I-129 with USCIS, or the worker leaves and applies for a new period of admission at a port of entry. Only the first creates the 240-day rule. Under 8 CFR 274a.12(b)(20), a TN worker whose extension was timely filed may continue working for the same employer for up to 240 days after the stay expires, ending early if USCIS denies the petition. On Form I-9, per M-274 Section 7.7:

1. File Form I-129 for the extension before the current stay ends.
2. Keep a copy of the I-129, proof of the fee and proof of mailing with the Form I-9; once the Form I-797C receipt notice arrives, keep that instead.
3. When the current authorization expires, write "240-day Ext." and the date you submitted the I-129 in the Section 2 Additional Information field.
4. When USCIS approves, the Form I-797 comes with a new I-94. Complete Supplement B with the document title, number and expiration date, and give the worker the I-94.
5. If 240 days pass first, or the petition is denied, reverify by then with any List A or List C document the worker chooses, or the worker cannot keep working.

If the worker is instead readmitted at the border with a new I-94 before the old one expires, record the new I-94 on Supplement B. Either way, reverify no later than the date the recorded authorization expires.

Can a TN worker start with a new employer as soon as the petition is filed?

No, and this is the biggest difference from H-1B. Under 8 CFR 214.6(i)(1), a TN worker who wants to change or add an employer must have the new employer file Form I-129, and "employment with a different or with an additional employer is not authorized prior to Department approval of the request." The other route is readmission at a port of entry with documents from the new employer (214.6(i)(2)). H-1B and H-2 workers can start on a properly filed petition; TN workers cannot.

For the transfer rows, the form "can move" because M-274 Section 8.0 treats a transfer between distinct units of the same employer as continuing employment.

What are the 10-day and 60-day windows?

8 CFR 214.1(l)(1) lets a TN worker be admitted for the validity period plus up to 10 days before it begins and 10 days after it ends, but "the alien may not work except during the validity period." Section 214.1(l)(2) adds a grace period after a job ends of up to 60 consecutive days, or until the validity period ends if that is sooner, once per validity period. During it the person keeps their status but may not work unless 8 CFR 274a.12 authorizes it. Two practical consequences: do not set a start date inside the 10 days before the validity period, and if the approval notice shows an end date earlier than the I-94, plan the extension around the earlier date.

What about TD spouses and E-Verify?

A spouse or child in TD status "shall not accept employment in the United States unless otherwise authorized under the Act" (214.6(j)(4)), and USCIS's TN page says TD family members may study but are not permitted to work. If a TD spouse applies to you, ask the same two work-authorization questions you ask everyone, covered in work authorization questions in interviews, and let Form I-9 do the rest after an offer. For E-Verify employers, a new TN hire gets a case like any new hire; an extension or readmission is handled on Supplement B, because the E-Verify User Manual says not to create a new case for reverification.

A TN Form I-9 checklist

• Calendar each TN worker's I-94 end date and the approval notice's end date, and start extensions early.
• Accept passport plus I-94, or a List B document plus the I-94, or any other valid choice.
• Write "240-day Ext." and the I-129 filing date the day the old authorization ends.
• Complete Supplement B when the new I-94 arrives, by approval or readmission.
• For a worker joining from another TN employer, set the start date only after approval or readmission.
• Check corporate structure before an internal move; a separate legal entity changes both the TN and the Form I-9 picture.