Employer Toolkit for Certificate of Sponsorship

If you hold a sponsor licence in the UK, understanding how a Certificate of Sponsorship (CoS) works is essential to avoid delays, refusals, and compliance risks.

Many employers search for “CoS UK requirements” expecting a list of documents required for the application. In practice, the process is based on accurate SMS entries, correct role classification, and audit-ready records.

This guide explains how the CoS process works in practice—what the Home Office actually assesses, and where sponsors most commonly face issues.

What Is a Certificate of Sponsorship (CoS UK)?

A Certificate of Sponsorship (CoS)  is not a physical document or certificate. It is an electronic record that contains details about the worker a sponsor is sponsoring and the job they will be doing.

By assigning a CoS, a sponsor confirms that:

• The role is genuine 

• The worker meets the relevant immigration requirements 

• The business is authorised to sponsor under the correct visa route 

• Sponsor duties will be met throughout the employment 

  
  

CoS UK Process: Request vs Assignment

Understanding the difference between these two stages is critical for managing risk.

Defined CoS (Workers Outside the UK)

A Defined CoS must be requested from the Home Office before it can be assigned.

Process:

• Submit role details via SMS 

• Home Office reviews the request 

• Approval is granted or further information may be requested 

  
  

Processing times:

• Defined CoS for overseas skilled workers are usually approved by the UK Home Office within one working day. However, this is typically the case only for straightforward applications. If further information or checks are required, the process may take 10 to 15 working days or longer.

Common issue:

If the job description is vague or does not clearly align with the selected SOC code, the Home Office may:

• Request further information 

• Delay approval 

• Refuse the request 

  
  

Undefined CoS (Workers Inside the UK)

An Undefined CoS is assigned from your annual allocation.

• Assigned directly from your annual allocation if you are given one automatically. No prior Home Office approval is required.

  
  

• If you are not given an allocation or you run out of COS, you can request additional COS through the SMS. These must be approved by the Home Office before they can be assigned.

  
  

• Requests for Undefined CoS for workers already in the UK currently take around 4–18 weeks under standard processing, with many cases experiencing delays of 16–18 weeks. If priority services are available, processing may be reduced to around 5 working days.

  
  

CoS Assignment

Once a CoS is available, it can be assigned to the worker through the SMS.

At this stage, the sponsor is confirming that:

• All information entered is accurate 

• The role and salary meet immigration requirements 

• The business is compliant with sponsor duties 

  
  

CoS Requirements UK: What Sponsors Must Get Right

The Home Office is assessing the credibility of the role and the accuracy of the data, not simply checking paperwork.

1. Genuine Vacancy and Role Alignment

You must be able to demonstrate:

• The role genuinely exists within your business 

• Duties align with the selected SOC code 

• The position reflects real business need 

Supporting records typically include:

• Detailed job description 

• Evidence of how the role fits within the organisation 

• Organisational structure (where relevant)

  
  

2. Salary Compliance

As of April 2026, a Skilled Worker’s salary must usually meet both:

• the general salary threshold of £41,700 per year; and 

• the relevant occupation’s going rate, 

with the higher requirement applying.

In most cases:

• Only guaranteed basic gross pay counts 

• Working hours must be clearly defined 

• Going rates are based on a 37.5-hour week and must be pro-rated accordingly 

Important exceptions

Lower salary thresholds may apply where permitted under immigration rules, including:

• New entrants to the labour market 

• Roles requiring a relevant PhD (including STEM PhDs) 

• Jobs listed on the Immigration Salary List 

• Certain health, care, and education roles 

• Some transitional arrangements 

Sponsors must ensure the correct salary option is applied based on the worker’s circumstances.

3. Consistency Across Records

The information entered on the SMS must match internal documentation, including:

• Employment contract 

• Job title and duties 

• Salary and working hours 

• Work location 

  
  

Any discrepancies can trigger Home Office scrutiny during an audit.

4. Worker Verification (Pre-Assignment Checks)

Before assigning a CoS, sponsors should verify:

• Identity (passport) 

• Immigration status and right to work in the UK (if the worker is already in the UK) 

• Contact details 

  
  

These checks form part of wider sponsor duties and should not be overlooked.

Immigration Skills Charge (ISC)

Sponsors must pay:

• CoS assignment fee: £525

• Immigration Skills Charge (ISC): 

  • £480 per year (small sponsors) 

  • £1,320 per year (medium or large sponsors) 

    
    

These costs must be paid by the employer and cannot be passed to the worker.

Proof of payment should be retained for compliance purposes.