Certificate of Sponsorship UK

Key points: Certificate of Sponsorship UK (2026)

A Certificate of Sponsorship (CoS) is a digital reference number issued by a UK employer that holds a sponsor licence. It is required for most sponsored UK work visa applications and confirms that a migrant worker has a genuine job offer that meets Home Office requirements.

In this article, we discuss:

What a Certificate of Sponsorship is
How much a CoS costs in 2026
Who issues a CoS and how it works
The difference between defined and undefined CoS
employer sponsorship duties and rules
Immigration Skills Charge (ISC) costs
common mistakes that lead to visa refusals

What is a Certificate of Sponsorship (CoS)?

A Certificate of Sponsorship (CoS) is an electronic record issued by a UK employer that holds a valid sponsor licence. It is required for most sponsored work visa applications and links a migrant worker to a specific job that meets UK immigration requirements.

A CoS is not a physical document. Instead, it is a unique reference number used by the Home Office to assess whether a worker meets the conditions for a sponsored visa, such as the Skilled Worker visa.

In practice, official UK government guidance confirms that a CoS establishes that:

A UK employer has offered you a genuine job
The employer is approved to sponsor overseas workers
The role meets UK visa skill and salary requirements
Your job details are recorded in the Home Office system
You are eligible to apply for a sponsored work visa

Who issues a Certificate of Sponsorship?

A CoS can only be issued by a UK employer that holds a valid Home Office sponsor licence.

Employers must:

be approved by UK Visas and Immigration (UKVI)
Use the sponsorship management system (SMS)
ensure the job meets immigration rules
comply with ongoing sponsor duties

Without a sponsor licence, an employer cannot issue a CoS.

What is a Certificate of Sponsorship used for?

A CoS is used to:

support Skilled Worker visa applications
link a worker to a licensed UK employer
Confirm job eligibility under immigration rules
allow the Home Office to assess sponsorship compliance

Most UK work visa routes require a CoS before applying.

How much does a Certificate of Sponsorship cost in the UK (2026)?

The Certificate of Sponsorship itself has a Home Office fee.

CoS fee (2026):

£525 per CoS: However, this is only one element of the overall cost of sponsoring a worker. Employers may also be required to pay additional sponsorship-related costs, depending on the visa route and circumstances.

Immigration Skills Charge (ISC)

Most employers are also required to pay the Immigration Skills Charge (ISC) when sponsoring a worker under the Skilled Worker route.

ISC rates (2026):

Small sponsor: £480 per year per sponsored worker
Large sponsor: £1,320 per year per sponsored worker

Are there exemptions?

The Immigration Skills Charge is not payable in certain cases, including where the worker is sponsored under the Health and Care Worker visa route, or where the application involves specific permitted in-country switching routes such as certain student-to-work transitions under the Immigration Rules.

Certificate of Sponsorship cost breakdown (2026)

Cost type	Small sponsor	Large sponsor	Paid by
Certificate of Sponsorship	£525	£525	Employer
Immigration Skills Charge (per year)	£480	£1,320	Employer
Sponsor licence (amortised)	£536 – £611	£1,476 – £1,682	Employer

The UK Home Office classifies sponsor size using specific financial and staffing thresholds that broadly align with Companies Act 2006 criteria. These thresholds determine whether a business is treated as a small or large sponsor, which in turn affects fees such as the Immigration Skills Charge.

Total cost of sponsoring a worker in the UK

The total cost of sponsoring a worker is significantly higher than the CoS fee alone.
For a typical 3-year Skilled Worker visa:

Estimated total employer cost:

Small sponsor: £2,500 – £4,500+
Large sponsor: £4,000 – £7,000+

This includes:

CoS fee
Immigration Skills Charge
sponsor licence costs (spread across workers)

Employers are not allowed to pass the Immigration Skills Charge to employees.

What are the Two Types of Certificates of Sponsorship?

Defined CoS

Used for Skilled Worker visa applicants applying from outside the UK.

must be approved by the Home Office,
requested individually by the employer, and
required before the visa application

Undefined CoS

Used for applicants already inside the UK.

used for visa extensions,
used for visa switching applications,
allocated under the sponsor licence quota

Defined vs undefined CoS comparison

Type	Location	Approval
Defined CoS	Outside UK	Home Office approval required
Undefined CoS	Inside UK	Employer allocation

How does a Certificate of Sponsorship work?

The CoS process follows four steps:

Step 1: Job offer

You receive a job offer from a UK licensed sponsor.

Step 2: CoS assignment

Your employer assigns a Certificate of Sponsorship.

Step 3: Visa application

You use the CoS reference number in your visa application.

Step 4: Home Office decision

UKVI assesses:

job eligibility
salary threshold
immigration compliance
applicant suitability

How long is a CoS valid?

A Certificate of Sponsorship is valid for 3 months from the date it is assigned.

If not used:

it expires
A new CoS must be issued

Can a Certificate of Sponsorship guarantee a visa?

No. A Certificate of Sponsorship (CoS) is a mandatory requirement for most sponsored UK visa routes, but it does not guarantee that a visa will be granted.

A CoS simply confirms that a UK-licensed employer has offered you a qualifying role under the immigration system. However, the Home Office will still carry out a full assessment of your application, including:

Your overall eligibility under the relevant visa route
the accuracy and completeness of supporting documentation
compliance with all applicable Immigration Rules and requirements

Visa approval is only granted where all criteria are satisfied.

Do all UK visas require a Certificate of Sponsorship (CoS)?

No. A Certificate of Sponsorship (CoS) is only required for specific sponsored work visa routes where an approved UK employer is acting as your sponsor.

A CoS is mainly required for:

Skilled Worker visas
Temporary Worker visas
other employer-sponsored immigration routes

It is not required for most unsponsored visa categories, including:

spouse or family visas
visitor visas
student visas (in most cases, unless switching from certain sponsored routes)

Skilled Worker visa and Certificate of Sponsorship

Most CoS applications relate to the Skilled Worker visa route.

Applicants usually need:

valid CoS
eligible job offer
salary threshold compliance
English language requirement

Common Mistakes with Certificates of Sponsorship

Common errors include:

incorrect occupation codes
wrong salary level
expired CoS used in applications
employer without a sponsor licence
The job is not meeting the Skilled Worker rules

Even small errors can result in refusal. Read our guide on the Top 6 mistakes UK employers make when sponsoring skilled workers that can lead to a refusal.

Should you seek legal advice?

Legal advice may help where:

Sponsorship eligibility is unclear
Occupation codes are complex
Compliance issues exist
Previous refusals have occurred

Not all applicants require full representation; some benefit from a document review or eligibility check.

Certificate of Sponsorship legal support from Mulgrave Law

Immigration solicitors at Mulgrave Law assist both employers and applicants with Certificate of Sponsorship and Skilled Worker visa matters.

We can help you:

Assess sponsorship eligibility
confirm CoS type (defined or undefined)
review occupation codes and salary levels
Check sponsor licence compliance
Prepare Skilled Worker visa applications

Book an appointment with an industry expert to discuss how we can help.

Frequently asked questions about Certificate of Sponsorship

1. What is a Certificate of Sponsorship?

A CoS is a digital reference number issued by a UK employer required for sponsored work visas.

2. How much does a CoS cost?

A CoS costs £525 in 2026.

3. Who pays for a Certificate of Sponsorship?

The employer must pay all CoS and Immigration Skills Charge costs.

4. What is the difference between defined and undefined CoS?

Defined is for outside UK applications; undefined is for inside UK applications.

5. How long does a CoS last?

A CoS is valid for 3 months.

Certificate of Sponsorship (CoS) UK: Meaning, Cost, Types And Requirements Explained (2026)