Social Insurance Number in Canada: Why You Need It

Dec 4, 2025

The Social Insurance Number, or SIN, is a government-issued private identifier that’s connected to your personal, income tax, and benefits information.

Written by Siddhi Bagwe

Editor & Content Strategist

Edited by Beth Buczynski

Head of Content, New Markets

Written by Siddhi Bagwe

Editor & Content Strategist

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A Social Insurance Number, or SIN, is a 9-digit number issued to Canadians and temporary residents by Service Canada — a federal service centre providing employment, tax, and benefits-related assistance.

A Social Insurance Number enables citizens, permanent residents, temporary residents to legally work, report earnings, manage taxes, and access government benefits in Canada.

SINs are issued in one of two ways: on paper, via a SIN confirmation letter, and in a digital format, accessible when you sign into or register for My Service Account Canada.

SINs processed before 2014 were often issued as a plastic card. As long as your plastic SIN card isn't expired or damaged, it's still valid. Note: If you're a Canadian citizen, your SIN can't expire.

Who needs a SIN number in Canada?

The situations that require a SIN often vary depending on your residency status. Here are some common examples:

Why is the SIN number important?

The SIN number is important because it’s tied to your profile containing personal, tax and CPP information in government records.

Your SIN is a private identifier that should legally only be used by you.

Failing to safeguard your SIN could lead to identity theft and fraud. Privacy risks include someone using your information to make purchases, racking up bills for you, misuse of government benefits, working illegally and more.

To prevent fraud from happening, it’s important to know when a SIN is or isn’t legally required as well as ways to protect your privacy.

A SIN is not required by law in all circumstances. Instances when you should not share it include:

To prove your identity.
In job or college applications.
For rental negotiations or leasing.
Signing up for utilities or non-government services.
In medical forms or surveys.

Alternatively, if a person or company requests your SIN, but you're not sure if you're legally required to provide it, ask them:

Am I legally obliged to give you my SIN number?
Why do you need my SIN number?
Who will use or have access to my SIN number if I provide it?

If you still have concerns after hearing their answer, offer another form of identification instead of the SIN. In most cases, you’ll be able to move forward with your transaction.

If the person or business persists, you may need to speak to a manager or legal professional to escalate the matter. Never provide your SIN if you're unsure, uncomfortable or feel unsafe.

Your SIN is a crucial, private piece of information. Here are some ways to keep it safe:

Don’t carry the SIN in your purse or wallet: remember it’s not to be used as an ID. Instead, keep it somewhere safe where you can find it when needed.
Shred — do not recycle — paper records that contain your SIN when they’re no longer needed. These include tax slips, notices of assessment, and registered contribution account statements.
Before providing your SIN number, confirm that you’re interacting with a legitimate organization and that it’s required by law.
Never send your SIN number via email or text message, or reply to unknown requests asking for your personal information.
Be cautious about providing your SIN over the phone. Only do so if you initiate the call and it’s legally required.
Keep your SIN record updated with the changes or corrections to your personal information, such as your address.
Report any suspected fraud or a compromised SIN immediately.

If you want to learn more about your responsibilities and Service Canada’s commitment to ensuring your SIN number is safe, visit the Government of Canada’s Social Insurance Number Code of Practice.

Maintain your SIN’s validity

To work in Canada, you need to have a Social Insurance Number.

International students, foreign workers and refugees are required to apply for a unique SIN starting with the digit “9.” This type of SIN has an expiry date, and must be renewed in order to remain valid

An employer will require you to provide a valid SIN, study or work permit and proof of address at the time of your employment — and before extending your work contract.

You can apply for a SIN online at sin-nas.canada.ca/en/Sin, in person at a Service Canada office, or by mail. To be approved you’ll need to:

Meet all eligibility requirements.
Provide all necessary supporting documentation.
Complete the application.
Submit the application.

Frequently asked questions

Does everyone have a Social Insurance Number in Canada?

Yes, all permanent residents, citizens and temporary residents in Canada, if eligible, require a SIN to work, manage taxes, and access government-assisted programs.

Is it safe to give my Social Insurance Number?

It’s safe to give your SIN number:

To your employer, after being hired.
To CRA, when entering your income tax information.
To the financial institution, when opening an interest-earning account.
To the Government of Canada, when accessing government programs and benefits.

Sources

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