900 Series SIN Number Expiry — The Trap That Hits When Your Work Permit Renews
900 series sin number expiry is the single most avoidable payroll disaster newcomers on a work permit run into, and it happens precisely because two things that feel like they should be linked — your permit and your SIN — are not automatically linked at all.
The mistake, in one sentence
You renew your work permit in good time, everything gets approved, and then a paycheque simply doesn’t land. Why did my paycheque stop canada sin is one of the most common panicked searches from newcomers who’ve just discovered that renewing their immigration document did nothing to renew the number tied to their payroll.
Why this happens
Sin number expires with work permit canada is the underlying rule: every Social Insurance Number issued to a temporary resident — someone here on a work permit or a study permit with work authorization — starts with the digit 9. That “900-series” number is deliberately tied to the expiry date of the document that got you into Canada. A regular SIN, issued to citizens and permanent residents, never expires. A 900-series SIN expires on exactly the date your permit does, whether or not you’ve since applied for and received a new one.
Renewing the permit is a completely separate government process from extending the SIN’s expiry date to match it. Nothing connects them automatically. Your employer’s payroll system, however, is watching the SIN expiry date closely, and once it lapses, payroll is often required to stop processing your pay until you show proof of an updated, valid number.
How to actually avoid it
- The moment your new or renewed work permit is in hand, go back to Service Canada and have the SIN’s expiry date extended to match it; don’t assume this happens in the background.
- Do this before your old permit’s expiry date, not after, so there’s no gap between the two documents.
- There is no fee for this. Applying online typically takes about five business days once your documents are complete; applying by mail is closer to 20 business days, so build in that lead time if you’re doing it by post.
- If a colleague or agency asks you to pay for SIN-related paperwork, that’s a red flag — the government charges nothing for this.
The bigger pattern worth remembering
Extending a temporary SIN number in Canada is really just one example of a broader rule: immigration documents and the administrative systems built on top of them (payroll, banking, provincial health cards) don’t sync themselves. Every time you renew a permit, it’s worth running through everything downstream of it — SIN, health coverage, driver’s licence — rather than assuming a successful renewal cascades automatically. Treat 900 series sin number expiry as a standing reminder to set on your calendar every time an immigration document changes.
If your permit renewal is delayed or your situation involves gaps in status, that’s a conversation for a licensed immigration consultant or lawyer, not a payroll department — they can only tell you your SIN has expired, not what your options are if your permit hasn’t been renewed in time.