SIN privacy guide: who can ask, and when to say no.

When you have to give your SIN

Service Canada says to only provide your SIN when the law requires it, and lists employment, financial accounts and government services as situations where it is required. Employers need it to report your income for tax and social benefit purposes, and Service Canada notes it is needed only after you are hired and begin earning income.

When you do not have to

Service Canada lists situations where you do not have to provide your SIN, including job applications, credit cards, renting property, and phone and internet service. It notes one exception: Hydro-Québec, which must collect it under provincial law. It also says you cannot be denied a product or service for refusing to provide your SIN when it is not legally required. This is a summary, so read the linked page for the exact wording.

Questions to ask before you share it

Service Canada suggests asking whether it is legally required, why it is needed, how it will be used and who will have access to it. If it is not required by law you can choose whether to share it, understanding the risk of fraud or identity theft. It calls requests from businesses “strongly discouraged, but not illegal”, and adds that your SIN card and confirmation letter are not identity documents, so use a passport or driver’s licence to prove who you are.

If a business asks for your SIN when it is not required, Service Canada suggests explaining that it is not required by law and offering other identification. If service is denied, you can speak with the person in charge or file a complaint with the Office of the Privacy Commissioner of Canada.

Keeping it safe

• Service Canada advises avoiding writing down or carrying your SIN unless necessary.
• Do not keep your SIN card or confirmation of SIN letter in your wallet or bag. Store them in a locked cabinet or safe, or on password-protected devices.
• Service Canada says your SIN is private, that it is illegal for anyone else to use it, and that you are responsible for protecting it.

If your SIN is lost or misused

For a lost or damaged card or letter, Service Canada has a separate page. A new SIN may be issued only if there is clear evidence that your current SIN has been used fraudulently. If someone else is using your SIN or it was in a data breach, Service Canada has a dedicated page; start from its protect your SIN page.

For employers

Service Canada tells employers that their employees’ SINs are confidential and should only be used for income-related information, and to store personal information in a secure area or on an encrypted system. The employer SIN checklist has the collection deadlines.

Checking a number without sharing it

Checking a typed SIN for typos does not need a server: the SIN validator, validation guide and temporary SIN checker run entirely in your browser. For fixtures, use the test number generator rather than a real SIN. Compare identifiers in SIN vs BN vs ITN.

Frequently asked questions

Do I have to give my SIN to a landlord?

Service Canada lists renting property among situations where you do not have to provide your SIN.

Does an employer need my SIN before I am hired?

Service Canada says the SIN is required only after you are hired and begin earning income, so an employer should not need it before then.

Can a company refuse me service if I will not give my SIN?

Service Canada says you cannot be denied a product or service for refusing to provide your SIN when it is not legally required.

Should I carry my SIN card?

No. Service Canada advises not keeping the card or confirmation letter in your wallet or bag.

Can I get a new SIN if mine was leaked?

Service Canada says a new SIN may be issued only if there is clear evidence that your current SIN has been used fraudulently.

Sources (retrieved October 2026): Service Canada: Social Insurance Number; Service Canada: Protect your SIN; Service Canada: Employer information, SIN. TNAADO is not affiliated with the Government of Canada; this page is general information, not legal or immigration advice.