A Social Insurance Number (SIN) is required for employment in Canada and to access various government programs and benefits, including Employment Insurance and the Canada Pension Plan.
Is everyone eligible for a SIN?
If you are a student permit holder, your permit may not allow you to accept employment in Canada. In that case your permit will probably have a statement similar to: “Unless authorized, prohibited from engaging in employment in Canada”. This is especially a common clause for students under 16 years old. With such a permit or with your sole visitor visa (without any permit), you cannot apply to receive a SIN number.
In line with your application, your student permit may allow employment with a remark similar to: “May accept employment on or off campus if meeting eligibility criteria as per …” Depending on the to-date federal and provincial restrictions, you are likely to be allowed for 20 hours of work per week with such a student permit. Once again depending on the exact statements in your study permit, you may also be allowed to work in campus/school premises, which will not be deducted from your 20 hour/week employment eligibility. Since federal and provincial governments have the power to change and adjust requirements of immigration, details and your eligibility must be consulted to a professional, preferably specialized for your province.
How can one acquire a SIN number?
Study permit holders with capacity to work part time, as well as work permit holders can apply to receive a SIN number. The person will have to visit Revenue Canada with the relevant documentation such as a valid ID and Permit to apply for a SIN number.
Why should one acquire SIN number?
SIN is a must for employment in Canada. While accepting a job position, they will need to comply with criteria defined in their permit because certain occupations require health checks to ensure public health and/or certification. When you are hired for a position, it is not mandatory for employees to show physical proof of SIN, yet you will be required to provide a SIN.
SIN allows you to access benefits and services from government programs such as Employment Insurance, Canada Pension Plan etc.
SIN also becomes valuable during tax filing. If you are ineligible for a SIN, you should consult to a Tax Clinic or professional to understand if you are obliged to file taxes. In a case it is mandated for you to file taxes, yet you are not eligible for a SIN via permit, you can apply for an Individual Tax Number (ITN) for tax purposes.
All in all, you should protect your SIN against identity theft.
Disclaimer: Please be reminded that context above provides general information and every individual must be evaluated case by case in terms of immigration pillars in Canada. To ensure a healthy immigration status, you must consult a professional as federal and provincial governments may have different requirements or may change applications temporarily or permanent.
Reference point: https://www.canada.ca/en/employment-social-development/programs/ei/ei-list/ei-employers-sin.html