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where can i find my sin number

You can usually find your Canadian SIN (Social Insurance Number) in a few standard places, or request it again from the government if you’ve lost all records.

Quick places to check

Look for your SIN on:

  • SIN confirmation letter from Service Canada (paper letter you got when first issued your SIN).
  • Old SIN card (plastic card is no longer issued, but older ones are still valid if you have one).
  • Tax documents:
    • T4 slips from employers
    • Income tax returns
    • CRA Notices of Assessment
    • RRSP or other CRA-related slips
      These often show your full SIN (sometimes with some digits masked).

If you recently applied online, you may also be able to view and print your SIN in your My Service Canada Account (MSCA) once your application is processed.

If you can’t find it anywhere

If you truly cannot locate your SIN on any documents:

  1. Use My Service Canada Account (if eligible).
    • Sign in or register for MSCA via Canada.ca, then select “Social Insurance Number” to view it, as long as your SIN application is on file.
  1. Ask Service Canada for help.
    • You can request a reissued Confirmation of SIN letter at no cost.
 * Ways to apply:
   * In person at a Service Canada Centre (fastest: they can print your confirmation letter on the spot).

   * Online via the SIN application portal (they’ll mail the confirmation letter).

   * By mail, using the official SIN application form and required documents.

  1. Prepare your documents.
    Service Canada normally asks for:

    • Proof of identity and status in Canada (e.g., birth certificate, permanent resident card, or other immigration documents, depending on your situation).
 * Proof of address for some application types.

Important safety tips

  • Your SIN is sensitive: only share it with trusted parties who are legally allowed to request it, such as employers, banks (for tax reporting), or government agencies.
  • Do not keep it in your wallet or send it casually over email or text.
  • If you suspect your SIN is stolen or misused, contact Service Canada and the CRA to report possible identity theft and get advice on next steps.

TL;DR: Check your SIN letter/card and CRA tax documents first; if you still can’t find it, use My Service Canada Account or request a new confirmation letter from Service Canada with your ID.