International students

Work and internships
Students who want to work (either on or off campus) must obtain a Social Insurance Number. The SIN does not provide medical coverage; it simply identifies a worker for income tax purposes.
Your Social Insurance Number will remain valid for so long as your study permit does not expire. To find out more about the SIN, visit the Government of Canada online or go in person to your nearest Service Canada office.
To find the closest Service Canada office, call 1-800-808-6352 or visit their directory:: http://www.rhdcc.gc.ca/cgi-bin/hr-search.cgi
How do I get a SIN?
Go to a Service Canada office to fill out application (or download the application form).
Two pieces of identification are required (originals only). Acceptable identification includes:
You must also bring your offer of employment or contract, unless you have an off-campus work permit.
The offer of employment must include:
Here is a sample contract (in french) suggested by Human Resources Canada. Employers are not obliged to use it, provided their document complies with the requirements listed above.
It normally takes three weeks to receive your SIN card; however, you can obtain your Social Insurance Number within 24 hours of applying.
Most international students receive a SIN starting with the number “9.” You need to provide your employer with this information.
Students with implied status regarding their immigration papers should read the following:
http://www.servicecanada.gc.ca/eng/sin/employers/expiry.shtml