A Certificate of Sponsorship in the UK is an electronic record assigned to a worker by a licensed UK sponsor, usually an employer. It gives the worker a unique reference number to use in a sponsored work visa application. Despite the name, it is not a paper certificate, not a visa, and not permission to start work on its own.
If you have been offered a UK job and your employer says they will “issue a CoS”, they usually mean they will assign this electronic sponsorship record through the Home Office Sponsorship Management System. The CoS links you, the employer, the job, the salary, the occupation code and the proposed employment dates together in one official record.
A CoS is most commonly discussed in relation to the Skilled Worker visa, but it is also relevant to other sponsored work routes. If you are unsure whether your proposed role needs sponsorship, Immigration UK can help you understand the route, the documents and the practical steps before an application is submitted.
What Is a Certificate of Sponsorship?
A Certificate of Sponsorship, often shortened to CoS, is a digital record created by a UK employer that holds a valid sponsor licence. The employer assigns the CoS to a named worker for a specific role. The worker then uses the CoS reference number when applying for the relevant work visa.
The CoS confirms important details about the sponsored employment, including the employer, job title, work location, salary, occupation code, hours and start date. It is one of the core parts of many sponsored work visa applications, but UK Visas and Immigration still assesses the visa application separately.
This means a CoS is not the same as being granted a visa. It does not automatically give you immigration permission, and it does not itself give you the right to work in the UK. You normally need the visa application to be approved before you can rely on the sponsored work permission.
Who Needs a Certificate of Sponsorship?
You will usually need a CoS if you are applying under a UK sponsored work route, such as the Skilled Worker route or certain Temporary Worker routes. British citizens, Irish citizens, people with indefinite leave to remain and some people with other forms of unrestricted work permission do not normally need employer sponsorship for that employment.
For many applicants, the CoS is the bridge between the job offer and the visa application. The employer must be approved to sponsor workers, the role must fit the immigration route, and the applicant must meet the visa requirements. A useful starting point for workers comparing options is Immigration UK's UK work visa guidance, especially if you are deciding which route applies to your circumstances.
Defined and Undefined Certificates of Sponsorship
There are two main types of CoS: Defined and Undefined. The difference matters because the wrong type can cause serious problems for both the employer and the worker.
- Defined CoS: generally used for Skilled Worker applicants applying from outside the UK. The employer must request the Defined CoS for the specific role and wait for approval before assigning it to the worker.
- Undefined CoS: generally used for Skilled Worker applicants applying from inside the UK, and for applicants on other sponsored work routes where the rules allow it. These usually come from the employer's annual CoS allocation.
An employer should not use an Undefined CoS where a Defined CoS is required. For example, if a Skilled Worker applicant is applying from overseas, the employer will normally need a Defined CoS. Getting this wrong can lead to delays, refusal risk and sponsor compliance action.
Who Issues a Certificate of Sponsorship?
The employer assigns the CoS, but only if it holds the right sponsor licence. The Home Office regulates the sponsorship system, approves sponsor licence applications and, where required, approves Defined CoS requests. In practical terms, the employer uses the Sponsorship Management System to create or assign the record.
Before assigning a CoS, the employer should check that the role is eligible, the salary meets the route requirements, the occupation code is appropriate, and the worker appears to meet the relevant visa criteria. The employer also takes on continuing sponsor duties, such as record keeping and reporting certain changes.
UKVI then decides the worker's visa application. Sponsorship is an important part of the process, but it is not the final decision. The applicant must still meet the Immigration Rules, provide the required evidence and avoid suitability issues, such as relevant immigration breaches or undisclosed refusal history.
What Information Appears on a CoS?
A CoS contains detailed information about the worker and the sponsored role. The exact fields depend on the route, but the record commonly includes the worker's name, nationality, date of birth, passport information and contact details.
It also includes employment information such as the employer name, sponsor licence number, job title, job description, occupation code, work address, weekly hours, salary, start date, end date and visa route. In some cases, it may also include information about maintenance certification or whether an ATAS certificate is relevant.
Accuracy is very important. The occupation code should match the real duties of the role, not simply the code that appears easiest to use. Salary, hours and work location should also reflect the actual arrangement. A mismatch can create questions for UKVI and, in some cases, can lead to refusal or sponsor licence problems.
How the Certificate of Sponsorship Process Works
The CoS process is usually led by the employer, but the worker still needs to understand the timing and information involved. A typical sponsored work application follows this sequence:
- The employer obtains the correct sponsor licence.
- The employer checks the role, salary, occupation code and worker details.
- The employer requests a Defined CoS where required, or uses an available Undefined CoS allocation.
- The employer assigns the CoS through the Sponsorship Management System.
- The worker receives the CoS reference number.
- The worker submits the relevant online visa application and supporting evidence.
- UKVI considers the application and makes a decision.
Once the CoS has been assigned, the applicant normally uses the reference number in the visa application. The applicant may also need other evidence, such as a passport, proof of English language ability, financial evidence where required, a tuberculosis test certificate where applicable, or route-specific documents.
If you are preparing a Skilled Worker application, Immigration UK's Skilled Worker visa guide can help you understand the wider visa requirements that sit alongside sponsorship.
How Long Is a Certificate of Sponsorship Valid?
A CoS must normally be used in a visa application within 3 months of being assigned. If it is not used in time, it will usually expire and the employer may need to assign a new CoS and pay the relevant fee again.
There is also an important start date rule. A worker must not apply for the visa more than 3 months before the job start date stated on the CoS. This is one of those timing rules that can easily be missed when everyone is focused on the job offer, relocation and paperwork.
The 3 month CoS use period should not be confused with the length of the visa. The CoS may state the proposed period of sponsorship, but the visa duration is decided under the Immigration Rules and the route being used.
How Much Does a Certificate of Sponsorship Cost?
As checked against GOV.UK information on 21 October 2026, the listed CoS fee is £525 for Worker licence certificates and £55 for Temporary Worker licence certificates. Fees can change, so employers and applicants should always check the current official position before relying on a figure.
The CoS fee is separate from other costs. In some routes, the employer may also have to pay the Immigration Skills Charge, which is separate from the CoS fee. The visa applicant may separately need to pay the visa application fee and the Immigration Health Surcharge, where applicable.
For official information on certificates, fees and the sponsorship process, GOV.UK provides dedicated Certificate of Sponsorship guidance for employers. This is the best place to confirm the latest government wording and figures before an application is prepared.
What Happens After a CoS Is Assigned?
After assignment, the employer should provide the CoS reference number to the worker. The worker should check that the personal and job details are correct before submitting the visa application. If something looks wrong, it is better to raise it early rather than hope UKVI will overlook it.
The worker should not assume that receiving a CoS means they can start work immediately. In most cases, they must wait until the correct immigration permission has been granted and the employer has completed the required right to work check.
The employer's duties also continue after the CoS is assigned. Sponsorship is not a one-time admin task. Sponsors must keep records, monitor sponsored workers and report relevant changes, such as certain changes in role, salary, work location or attendance.
Can a Certificate of Sponsorship Be Changed?
Some minor errors can be explained by the sponsor using a sponsor note, but not every problem can be fixed this way. If the wrong route, wrong occupation code or significant incorrect information has been used, a new CoS may be required.
Changes after the visa has been granted can also matter. A change of employer will usually require a new CoS and a fresh application. A major change in job duties or occupation code may also require a new application. Extensions normally require a new CoS as well, even where the worker is staying with the same employer.
If your circumstances are changing, Immigration UK's overview of UK visa sponsorship explains how sponsorship fits within the wider immigration process.
Common Certificate of Sponsorship Problems
Most CoS problems arise because the sponsorship details were not checked carefully before assignment. Common issues include an employer without the correct sponsor licence, the wrong CoS type, an expired CoS, an incorrect occupation code, salary concerns, or a withdrawn job offer.
A visa can still be refused even where a CoS has been assigned. The applicant might not meet the visa requirements, the job details might not satisfy the route rules, or the evidence may be incomplete. If an application is refused and the employer still wishes to sponsor the worker, a new CoS may be needed before a fresh application is made.
Professional support can be particularly useful where the worker is switching routes inside the UK, changing employer, applying after a previous refusal, or where the role does not fit neatly into an obvious occupation code. Careful preparation at the CoS stage can prevent a small mistake becoming a rather expensive headache.
Frequently Asked Questions
Is a Certificate of Sponsorship the same as a visa?
No. A CoS is an electronic sponsorship record used to support a visa application. UKVI must still approve the visa before the worker can rely on that immigration permission.
How long do I have to use my CoS?
You must normally use the CoS within 3 months of the date it is assigned. You should also make sure you are not applying more than 3 months before the job start date stated on it.
Can I apply for a UK work visa without a CoS?
If the route requires sponsorship, you will normally need a valid CoS reference number before submitting the application. Without it, the application is unlikely to meet the route requirements.
Who pays for the Certificate of Sponsorship?
The sponsor pays the CoS fee for the relevant sponsored route. Certain sponsor costs, including prohibited sponsorship charges, must not be passed to the worker.
Do dependants need their own CoS?
Dependants normally apply separately as dependants and do not need their own sponsored worker CoS. Their eligibility depends on the current rules for the main applicant's visa route.
