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Social Insurance Number (SIN)

A SIN is the 9-digit number employers need to report pay to the government. Ask for it within 3 days of a new hire's start and keep it confidential.

Also called: SIN, SIN number, temporary SIN, 9-series SIN

What social Insurance Number (SIN) means

A Social Insurance Number (SIN) is a 9-digit number issued by Service Canada. People need one to work in Canada and to get government programs and benefits. As an employer, you use it to report the employee's pay, deductions and insurable earnings, for example on T4 slips and Records of Employment.

You must ask each new employee for their SIN within 3 days after the day their employment begins, and keep a record of it. If the person does not have one yet, they can still start work; they should apply and give it to you once they have it.

A SIN that starts with 9 is issued to temporary residents, such as people on work permits. It is valid only until the expiry date on the immigration document that authorizes the person to work in Canada.

How it works

Ask for the SIN on or soon after the first day, as part of your payroll set-up. Keep a record of the number. Use the SIN only for income-related purposes such as payroll and tax reporting, not as an employee ID number.

Keep SINs confidential. Store them in a secure place, such as a locked cabinet or an encrypted payroll system, and limit who can see them. Do not print them on schedules, ID badges or anything visible to other staff.

For a SIN starting with 9, the SIN alone does not authorize work. Before hiring, check the person's work permit or other immigration document: the expiry date and any conditions, such as the employer, job and location. When the document is renewed, the employee updates their SIN record with Service Canada, and you check the new document and its expiry date.

If an employee applied to extend their status before it expired, their SIN may show as expired while IRCC decides. Service Canada says such a person may be able to keep working while the extension is processed. Keep a note of the date they applied and check the decision when it comes.

Is it the same in every province?

The SIN is federal and the rules are the same for every employer in Canada, including federally regulated employers and employers in Quebec.

Example: A garden centre hires a student

Elena runs a 12-person garden centre in Kamloops, British Columbia, and hires an international student for the spring. His SIN starts with 9.

On his first day, Elena records his SIN in her encrypted payroll system, then checks his study permit for the conditions on working and notes its expiry date. She makes sure the number does not appear on the staff schedule or anywhere other staff can see it.

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Staffkin HR Suite employee records keep profiles and documents in one place, which helps you keep sensitive details like SINs with limited access.

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Questions about social Insurance Number (SIN)

When does a new employee have to give me their SIN?

You must ask for it within 3 days after the day their employment begins. They can start work before the SIN is issued and give it to you once they have it.

What does a SIN starting with 9 mean?

It is issued to temporary residents. It is valid only until the expiry date on the immigration document that authorizes the person to work in Canada.

Is a SIN enough to show someone can work in Canada?

Not for a SIN starting with 9. Check the work permit or other immigration document, including its dates and conditions.

How should I store employees' SINs?

Securely, such as in a locked cabinet or an encrypted system, with limited access. Use the SIN only for income-related purposes like payroll.

Related terms

OnboardingOnboarding is how you bring a new hire into the job: paperwork, payroll set-up, safety.T4 slipA T4 slip reports an employee's pay and deductions for the year. You give one to each.Record of Employment (ROE)A Record of Employment is the federal form employers issue when a worker's earnings stop.TD1 formA TD1 form tells you which tax credits a new employee claims, so you can work out how.Employer-specific work permitAn employer-specific work permit lets a foreign national work only for the employer, job.Open work permitAn open work permit lets a foreign national work for almost any Canadian employer without.RL-1 slip (Relevé 1)The RL-1 (Relevé 1) is Quebec's year-end slip for employment income and deductions..All HR terms165 plain-language definitions

Official sources

General information for Canadian employers, not legal advice. Rules differ by province and territory and change over time, so check with your provincial employment standards office (or the federal Labour Program if you are federally regulated) before you rely on it. See employment standards by province.

Checked against official sources on 4 November 2026.