Sponsor guidance: understanding certificates of sponsorship

As UK businesses increasingly rely on international talent, understanding the Certificate of Sponsorship (CoS) is essential for legal compliance and successful visa applications. This article outlines the key aspects of CoS for employers and HR teams navigating the UK immigration system.

What is it?

A CoS is a digital document issued by a UK-licensed sponsor to a migrant worker. It is not a physical certificate, but an electronic record with a unique reference number that the worker uses when applying for their visa.

Think of it as a formal declaration: the employer confirms the job offer and that the role meets the visa requirements.

Types of CoS

• Defined CoS: For Skilled Worker applicants outside the UK. These must be requested individually via the Sponsorship Management System (SMS) as and when required.
• Undefined CoS: For Skilled Workers already in the UK or other visa categories. Sponsors estimate how many they’ll need at the application stage. An annual allocation will be provided, based on the previous year’s use. An increase in allocation must be requested if required.

Validity and timing

CoS are assigned via the Sponsorship Management System (SMS). Accuracy is critical, because substantive amendments cannot be made after the CoS is assigned; errors may require a new CoS and fee.

A CoS must be used within three months of being assigned.

The visa application must not be made more than three months before the job’s start date.

Costs and charges

Additionally, employers may need to pay the Immigration Skills Charge (ISC), depending on the visa type and duration, unless an exemption applies:

• £364 per year for small or charitable sponsors
• £1,000 per year for medium or large sponsors

The ISC is charged upfront based on the duration of sponsorship (max 5 years).

Partial or full refunds may apply if the visa is refused, withdrawn, or unused.

Compliance Obligations

Sponsors must:

• Assign CoS only for genuine vacancies.
• Ensure roles meet salary and skill thresholds.
• Maintain accurate records and report changes via SMS.
• Not pass CoS costs to the sponsored worker – a key compliance update.

It is important to be aware that non-compliance can result in licence suspension or revocation.

Need Help?

The Certificate of Sponsorship is more than just a formality; it’s a cornerstone of the UK’s immigration system. Employers who understand and manage CoS correctly not only stay compliant but also unlock access to a diverse and skilled global workforce.

Our immigration law team advises UK employers on:

• Sponsor licence applications
• Assigning CoS and compliance
• Visa strategy and workforce planning

Contact us today to ensure you meet your legal obligations and avoid costly errors.

FAQs

❓ Who needs a CoS?

Any foreign worker applying for a visa under the Skilled Worker or Temporary Worker routes must be assigned a CoS by their UK employer

❓ How do I assign a CoS?

You use the Sponsorship Management System (SMS) to create and assign CoS. Defined CoS must be requested and approved before being assigned; undefined CoS are allocated annually based on your licence.

❓ Can I pass CoS costs to the worker?

No. Sponsors must not pass on CoS fees or related administrative costs to the sponsored worker

❓ What are my responsibilities as a sponsor?

• Ensure the job meets visa requirements.
• Assign CoS only for genuine roles.
• Keep accurate records.
• Report changes via SMS.
• Comply with all sponsor duties to avoid penalties or licence revocation.