Introduction
If your business has a sponsor licence and plans to hire workers from overseas, you’ll almost certainly come across the term Certificate of Sponsorship (CoS).
Despite its name, a Certificate of Sponsorship is not a physical certificate. It is an electronic record created by a licensed sponsor that allows an eligible worker to apply for a UK work visa.
Assigning a CoS is one of the most important responsibilities for sponsor licence holders. Employers must ensure the information is accurate, maintain supporting records, and continue meeting UKVI compliance requirements throughout the employee’s employment.
This guide explains what a Certificate of Sponsorship is, when it is needed, how it works, and what employers should know before assigning one.
What Is a Certificate of Sponsorship (CoS)?
A Certificate of Sponsorship (CoS) is a unique electronic reference number issued by a licensed sponsor through the Home Office Sponsorship Management System (SMS).
The CoS contains important information about:
- The employer
- The employee
- The job role
- Salary
- Working hours
- Sponsorship details
The worker uses this reference number when applying for their visa.
A Certificate of Sponsorship is not the visa itself. Instead, it supports a visa application by confirming that a licensed sponsor is offering genuine employment.
Who Needs a Certificate of Sponsorship?
A Certificate of Sponsorship is generally required when a UK employer hires someone who needs sponsorship to work in the UK.
This commonly applies to workers applying under routes such as the Skilled Worker visa.
Workers who already have unrestricted permission to work in the UK usually do not require a CoS.
Before assigning one, employers should ensure the worker is eligible for sponsorship and that the role meets the relevant immigration requirements.
What Information Is Included in a CoS?
When assigning a Certificate of Sponsorship, employers must provide accurate information about both the role and the employee.
Typical information includes:
- Employer details
- Job title
- Occupation code
- Salary
- Working hours
- Work location
- Start date
- Personal details of the worker
Providing accurate information is important because errors can delay visa applications or create compliance issues later.
Defined vs Undefined Certificate of Sponsorship
There are two main types of Certificate of Sponsorship.
Defined CoS
A Defined CoS is generally used for workers applying for a Skilled Worker visa from outside the UK.
Employers usually need approval before assigning this type of CoS.
Undefined CoS
An Undefined CoS is generally used for workers applying from within the UK or under other eligible immigration routes.
Licensed sponsors receive an annual allocation of Undefined Certificates of Sponsorship that can be assigned when required.
The correct type depends on the worker’s circumstances and immigration route.
When Should Employers Assign a CoS?
A Certificate of Sponsorship should only be assigned after:
- Confirming the role is eligible
- Checking sponsorship requirements
- Preparing accurate employee information
- Ensuring the business holds a valid sponsor licence
Employers should carefully review all information before assigning a CoS, as changes may require further action.
Employer Responsibilities After Assigning a CoS
Assigning a Certificate of Sponsorship is only one part of the sponsorship process.
After the employee joins the organisation, employers should continue to:
- Complete right to work checks
- Keep immigration records updated
- Store supporting documents securely
- Monitor visa and eVisa information
- Report relevant changes where required
- Maintain sponsor licence compliance
Having organised HR processes helps employers manage these responsibilities more effectively.
Common Certificate of Sponsorship Mistakes
Some common mistakes include:
- Entering incorrect employee details
- Selecting the wrong occupation code
- Recording inaccurate salary information
- Losing supporting documentation
- Missing important immigration updates
- Failing to maintain accurate employee records
Carefully reviewing information before assigning a CoS helps reduce the likelihood of compliance issues.
How HR Software Helps Manage Certificate of Sponsorship Records
Managing Certificates of Sponsorship becomes more challenging as organisations sponsor more overseas workers.
HR software can help employers:
- Store CoS records securely
- Organise immigration documents
- Monitor visa and eVisa information
- Track compliance deadlines
- Manage sponsor compliance activities
- Prepare for UKVI audits
Having all compliance information in one place helps businesses remain organised throughout the employee lifecycle.
Final Thoughts
A Certificate of Sponsorship is an essential part of employing overseas workers in the UK. While assigning a CoS is a straightforward process, employers must ensure the information provided is accurate and continue meeting their sponsor licence responsibilities after the worker joins the organisation.
By maintaining organised employee records, monitoring immigration information, and following UKVI compliance requirements, businesses can reduce compliance risks while creating a smoother experience for both HR teams and sponsored workers.
