CERTIFICATE OF SPONSORSHIP (COS) APPLICATION

Defined & Undefined CoS for UK Work Visas

If your business wants to sponsor overseas workers under the UK Skilled Worker visa or other work routes, you must issue a Certificate of Sponsorship (CoS). This certificate confirms the job offer, salary, and sponsor licence details for a migrant worker.

There are two main types of CoS:

• Defined Certificate of Sponsorship – for Skilled Workers applying from outside the UK
• Undefined Certificate of Sponsorship – for Skilled Workers already in the UK, and other visa categories such as Intra-Company Transfer or Graduate Trainee

What is a Certificate of Sponsorship?

A Certificate of Sponsorship (CoS) is an electronic document issued by a UK-licensed sponsor to a foreign worker. It’s not a physical certificate, but a unique reference number that the worker must use when applying for a UK work visa.

Each CoS confirms:

• The job title and duties
• The sponsor’s details and licence number
• The salary offered
• The occupation code
• Confirmation that the job meets visa eligibility criteria

Defined vs. Undefined Certificate of Sponsorship

Understanding the difference between Defined and Undefined CoS is essential for compliance and successful recruitment.

Used for:

• Skilled Worker visa applicants applying from outside the UK

A Sponsor Licence is not required to employ:

• You must apply to UKVI for each Defined CoS through your SMS account.
• You cannot assign it instantly—you must wait for UKVI approval
• Once approved, the Defined CoS can be assigned to a specific worker, who can then apply for their visa.

When needed:

• When recruiting international talent from overseas who need a Skilled Worker visa.

Undefined Certificate of Sponsorship

Used for:

• Skilled Worker or other sponsored visa applicants already in the UK (switching from a different visa or extending)
  
  
• Other categories such as:
  
  
  • Intra-Company Transfer
  • Graduate Trainee
  • Temporary Workers (e.g., Creative, Charity, Religious workers)

How it works:

• Sponsors request a yearly allocation of Undefined CoS when they apply for or renew their sponsor licence.
• Once available in your account, they can be assigned instantly without approval from UKVI.

When needed:

• For in-country recruitment, visa extensions, or internal transfers

Our Support Services

Applying for and managing a CoS can be complex, especially for new sponsors. We’ll help you connect with a solicitor or immigration adviser who can:

• Assist with your Defined CoS requests via the Sponsor Management System (SMS)
• Advise on how many Undefined CoS to request in your annual allocation
• Prepare job descriptions, salary details, and compliance documentation
• Ensure your business meets all sponsorship duties and obligations
• Prevent CoS misuse or Home Office penalties
• Help correct errors or respond to a sponsor licence audit

Common Mistakes to Avoid

• Assigning a Defined CoS to an in-country applicant (incorrect usage)
• Failing to apply for a Defined CoS in advance of the visa application
• Using up your Undefined CoS allocation too early in the year
• Assigning a CoS before the job role or salary meets the minimum requirements
  
  

A solicitor or immigration specialist can help you stay compliant and avoid risks to your sponsor licence.