Introduction to Certificate of Sponsorship (CoS)

When you’re dreaming of working in the UK, one of the most vital documents you’ll encounter is the Certificate of Sponsorship (CoS). Think of it as your golden ticket — it bridges the gap between a UK employer’s job offer and your work visa application.

What Is a Certificate of Sponsorship?

A Certificate of Sponsorship is a digital document issued by a UK-licensed sponsor (usually an employer). It’s not a physical certificate — it’s an electronic record with a unique reference number that you’ll need when applying for your visa.

This reference number links your visa application to the job you’re being offered and confirms that the role is genuine and meets the UK Home Office’s requirements.

Importance of CoS in UK Immigration

Without a valid CoS, you cannot apply for most UK work visas, including the Skilled Worker Visa. It’s a mandatory step, ensuring that:

The job offer is legitimate
The employer is authorized
The role meets the salary and skill level required

Types of Certificate of Sponsorship

Defined Certificate of Sponsorship

When Is It Required?

A Defined CoS is required when the worker is outside the UK and is applying for a Skilled Worker visa.

Who Issues It?

The employer must apply to the Home Office for each Defined CoS. Once approved, they can assign it to the migrant.

Undefined Certificate of Sponsorship

Who Uses This Type?

This is used for workers already inside the UK — for example, switching from a Student visa to a Skilled Worker visa.

How It Differs From Defined CoS

Unlike the Defined version, employers can allocate undefined CoS themselves via the Sponsorship Management System (SMS), without needing Home Office approval each time.

Temporary Worker Certificate of Sponsorship

For Seasonal and Charity Workers

This category supports roles under the Temporary Worker routes, including:

Charity Work
Creative and Sporting roles
Seasonal jobs (e.g., agriculture)

Sector-Specific Usage

Each sector has specific rules — such as maximum duration, restrictions on family members, and visa extensions.

Key Requirements for a CoS

To issue a CoS, the job and employer must tick several boxes:

Only companies with a Sponsor License can issue CoS. This ensures that only reputable employers can hire overseas workers.

Genuine Job Offer

The role must be real, not created just to help someone gain a visa.

Salary Thresholds

As of 2024, the minimum salary for a Skilled Worker visa is £38,700/year, with exceptions for shortage occupations.

Appropriate Skill Level

The job must meet the RQF Level 3 or above (A-level equivalent or higher) unless exempt.

Financial Maintenance

Employers must confirm whether they will certify maintenance for the employee or whether the applicant will support themselves.

How to Apply for a Certificate of Sponsorship

Step-by-Step Guide for Sponsors

Accessing the Sponsorship Management System (SMS)

Sponsors log in to the Home Office’s SMS portal to manage their license and assign CoS.

Creating and Assigning a CoS

Employers fill in the job details:

Role title
Duties
Salary
Work location

Then, they assign it to the intended worker.

Submitting Details for Home Office Approval

For Defined CoS, details are submitted and reviewed. Approval usually takes 1 working day.

How Applicants Use the CoS

Once issued, the applicant uses the CoS reference number to apply for their visa through the UK Visas and Immigration portal.

Documents Needed for a CoS Application

For Sponsors

Company registration documents
Evidence of trading
HR systems proof
Job descriptions

For Migrants

Passport
Academic or professional qualifications
English language proof
CoS reference number

Validity, Expiry, and Usage of a CoS

How Long Is a CoS Valid?

A CoS is valid for 3 months from the date of issue. You must apply for your visa within that period.

Reusing or Cancelling a CoS

You cannot reuse a CoS. If an employee doesn’t use it, the sponsor must cancel it.

Important Deadlines

Visa applications tied to a CoS must be submitted within 90 days, and the start date should align with the CoS.

Costs Associated With a Certificate of Sponsorship

CoS Application Fee

Defined/Undefined CoS: £239

Immigration Skills Charge

Small sponsors: £364/year
Medium/Large: £1,000/year

Additional Costs for Sponsors

Sponsor License fee: £536 (small) / £1,476 (large)
Legal/consultancy fees (if used)

Common Reasons for CoS Rejection

Incomplete Documentation

Missing job details or inaccuracies will lead to rejections.

Invalid Job Role or Salary

Roles that don’t meet the standard occupation codes or salary thresholds get flagged.

Expired or suspended sponsor licenses lead to automatic denial.

Switching and Extending with a CoS

Switching from Student or Graduate Visa

Migrants can switch to a Skilled Worker visa using an Undefined CoS from a licensed sponsor.

Extending an Existing Work Visa

Employers issue a new CoS for visa extensions before the current one expires.

Eligibility Criteria

Must be a registered UK entity
Must have appropriate HR systems
No history of immigration violations

Application Process

Apply online
Submit supporting documents
Pay the license fee

Maintaining Compliance

Report changes in migrant status
Keep records
Cooperate with Home Office inspections

How to Check the Status of a CoS

For Sponsors

Log into the SMS portal to view issued or pending CoS.

For Migrants

Use your CoS reference number to track your application or contact your sponsor.

Tips for a Successful CoS Application

Accuracy and Transparency

Provide clear, verifiable job information. Don’t try to bend the rules — the Home Office checks everything.

Working with Immigration Advisors

Hiring immigration consultants can simplify the process and ensure you meet every requirement.

Recent Changes to CoS Rules (2024–2025)

Updates to Salary Thresholds

From April 2024, the salary threshold increased to £38,700, making it harder for some roles to qualify.

Sector-Specific Changes

Health and care roles have been exempted from the new threshold, allowing smoother entry.

Internal and External Resources

Conclusion

A Certificate of Sponsorship is the foundation of a legal and successful work visa application for the UK. Whether you’re an employer planning to hire international talent or a skilled worker seeking your dream job abroad, understanding the CoS system is crucial.

Ensure all requirements are met, use the right type of CoS, and consult with immigration experts if needed. With the correct approach, a CoS can open the door to new opportunities in the UK job market.