Certificate of Sponsorship (CoS)
Your Key to a UK Work Visa
What is a CoS? An electronic record, not a physical document. It contains your job details and sponsor information.
Types of Certificate of Sponsorship
| Type | Who uses it? | Validity |
|---|---|---|
| Defined CoS | Applicants applying from outside the UK | 3 months to apply after assignment |
| Undefined CoS | Applicants applying from inside the UK (switching or extending) | Immediate use (no expiration for assignment) |
What Information Does a CoS Contain?
- Your personal details (name, passport number)
- Job title and description
- Standard Occupational Classification (SOC) code
- Annual salary
- Start date
- Sponsor licence number
- Whether the role is on the ISL
- Maintenance certification (if applicable)
How to Get a Certificate of Sponsorship
1
Job offer
From a licensed sponsor
2
Employer requests CoS
From the Home Office sponsorship system (SMS)
3
CoS assigned
You receive a CoS reference number
CoS Validity Periods
- Defined CoS (outside UK): You must apply for your visa within 3 months of the CoS being assigned.
- Undefined CoS (inside UK): No fixed expiry for assignment, but your visa application must be submitted before your current visa expires.
Common CoS Problems & How to Avoid Them
Incorrect salary โ Ensure the CoS salary matches your offer letter and meets the minimum threshold.
Wrong SOC code โ The occupation code must accurately reflect your role.
Start date issues โ CoS start date should align with your visa application timeline.
Have a Certificate of Sponsorship?
We can review your CoS before you submit your visa application to avoid common errors.
Review My CoS Book Consultation