Certificate of Sponsorship Explained for Employers 2026

For Employers. A Certificate of Sponsorship (CoS) is the single most important document in a Skilled Worker visa application — and as the sponsoring employer, you are wholly responsible for creating it, paying for it, and ensuring every piece of information on it is accurate. Understanding the mechanics of the CoS process is not optional compliance box-ticking: errors at this stage can invalidate a worker's visa application, expose your organisation to formal UKVI action, and damage the trust of a recruit you may have spent months courting.

What Is a Certificate of Sponsorship?

Despite the name, a Certificate of Sponsorship is not a paper certificate or a formal letter. It is a digital record — a unique alphanumeric reference number generated inside UKVI's Sponsorship Management System (SMS) — that captures specific, structured information about the role you are offering, the salary attached to it, and the individual worker you intend to sponsor.

When the worker applies for their Skilled Worker visa on gov.uk, they enter this reference number as part of their application. UKVI then checks the information you entered against the requirements of the visa route. If anything does not match — the salary is below the relevant threshold, the SOC code does not correspond to an eligible occupation, or the worker's personal details differ from the passport — the application is liable to be refused.

The CoS is therefore not a formality. It is the foundation of the visa application, and it must be precise.

The Two Types of CoS: Defined and Undefined

Understanding which type of CoS to assign is one of the first practical decisions you will make as a sponsor, and conflating the two is a common and costly mistake.

Defined Certificate of Sponsorship

A Defined CoS is required when a worker is applying for a Skilled Worker visa from outside the United Kingdom. It is also used in certain limited in-country switching scenarios. Critically, Defined CoS are not drawn from an allocation you hold — each one must be individually requested from and approved by UKVI before you can assign it. This adds a step to the process and means you need to plan ahead, particularly if you are hiring workers who need time to arrange their affairs before travelling.

Undefined Certificate of Sponsorship

An Undefined CoS is used when the worker is already in the UK and is extending their existing Skilled Worker visa or switching from another eligible visa category. Undefined CoS are drawn from an annual allocation that UKVI grants to your organisation when you are approved as a sponsor. Your Authorising Officer can request additional allocation through the SMS if you exhaust your initial grant.

Who Can Assign a CoS in Your Organisation?

Access to the SMS — and therefore the ability to assign a CoS — is restricted to named individuals within your organisation. These are:

• Authorising Officer (AO): The senior, accountable person responsible for the licence. The AO holds overall responsibility for compliance.
• Key Contact: The primary liaison with UKVI.
• Level 1 Users: Individuals with full SMS access, including CoS assignment.
• Level 2 Users: More limited SMS access, typically used for day-to-day tasks.

Your Authorising Officer must be a settled person in the UK (British citizen, Indefinite Leave to Remain, or similar), and must not have an unspent criminal conviction for specified offences. Only Level 1 Users and above can assign a CoS. Assigning this access carelessly — for example, giving Level 1 access to an employee who later leaves the organisation — is a compliance risk that should be managed actively.

How to Assign a Certificate of Sponsorship: Step by Step

Step 1: Confirm Your Organisation Is Licensed and Has Allocation

Before you can assign any CoS, your organisation must hold a valid sponsor licence on the A-rated list. If your licence has been downgraded to B-rated (typically following a compliance visit that identified concerns), you cannot assign new CoS until you have worked through the action plan set by UKVI and been restored to A-rating.

For Defined CoS, you also need to request the CoS from UKVI and receive approval before the SMS will allow assignment.

If you are still in the process of obtaining your licence, our guide on how to apply for a UK Skilled Worker sponsor licence walks through the licence application process in detail, and our sponsor licence application documents checklist covers the supporting evidence UKVI expects to see.

Step 2: Verify the Role Meets Skilled Worker Requirements

Before opening the SMS, confirm the following:

• The role has an eligible Standard Occupational Classification (SOC) code listed on the Skilled Worker eligible occupations list.
• The salary you are offering meets both the general salary threshold for the Skilled Worker route and the going rate for that specific SOC code. UKVI applies whichever is higher.
• The role requires the worker to be physically present at a UK worksite (remote-only arrangements can complicate sponsorship and should be checked with a solicitor).

The general salary threshold and the going rates for individual SOC codes are published on gov.uk and are reviewed periodically. Verify the current figures directly — do not rely on third-party summaries that may not reflect the most recent changes.

Step 3: Carry Out a Right to Work Check

You must conduct a compliant right to work check on every employee before they start work, including sponsored workers. For workers who are overseas at the point of hire and who do not yet have their visa, the right to work check is conducted once they arrive and before they begin employment. UKVI guidance sets out the specific methods available — manual checks, online Home Office checks, and Identity Document Validation Technology (IDVT) via certified providers — and the method used matters for your statutory excuse in the event of a later compliance audit.

Do not skip or delay this step. Right to work checks are one of the first things a Home Office compliance officer will examine.

Step 4: Enter the CoS Details in the SMS

When you create the CoS record in the SMS, you will need to provide:

• The worker's personal details exactly as they appear in their passport (name, date of birth, nationality, passport number).
• The job title and SOC code.
• The salary — annual gross, and whether it is paid weekly, monthly, or annually.
• The start and end dates of employment.
• The work location(s).
• Whether the role includes any allowances being counted towards the salary threshold (there are strict rules about which allowances qualify).

The system will generate the unique CoS reference number once the record is saved and assigned.

Step 5: Pay the Immigration Skills Charge

For most Skilled Worker CoS assignments, you must pay the Immigration Skills Charge (ISC) at the point of assignment. The ISC is a levy on employers that exists to fund skills training in the UK workforce. As of 2026, the rates — which are reviewed by the Home Office — are structured according to employer size:

• Small or charitable sponsors pay a lower per-year rate.
• Medium or large sponsors pay a higher per-year rate.

The charge is calculated based on the total length of the sponsorship, rounded to the nearest six months. If you sponsor a worker for three years, you pay three years' worth of ISC at the applicable rate. Verify the precise current figures at gov.uk/uk-visa-sponsorship-employers before any assignment — the figures change and are not something you should rely on secondhand.

Some workers are exempt from the ISC — certain PhD-level roles, workers switching from specific visa categories, and a small number of other circumstances set out in the Immigration Skills Charge Regulations. Confirm exemptions with a licensed immigration solicitor if you believe they might apply.

For a broader breakdown of all costs involved in sponsorship — including the sponsor licence application fee, CoS fees, and the ISC — see our article on UK sponsor licence cost and fees breakdown.

Step 6: Share the CoS Reference Number with the Worker

Once the CoS is assigned and the ISC paid, you provide the unique reference number to the worker. They enter it into their online visa application. You do not submit the visa application on their behalf — that is the worker's responsibility.

Important: Remind the worker that they have three months from the date the CoS is assigned to submit their visa application. If they miss that window, the CoS expires and cannot be reactivated. A new CoS would need to be assigned, triggering additional costs.

Common Mistakes Employers Make — and How to Avoid Them

Getting a CoS wrong is more consequential than most employers expect. UKVI does not offer a simple correction service once a CoS has been used in a visa application. Here are the mistakes that appear most frequently — and the concrete fix for each.

1. Entering a salary below the going rate for the SOC code. The fix: before opening the SMS, look up the specific SOC code on the gov.uk going rate table and confirm your offer meets or exceeds it. The general threshold and the going rate are separate tests — both must be passed.

2. Using the wrong SOC code. A job title does not determine the SOC code — the actual duties of the role do. The fix: map the duties against the ONS SOC occupation descriptions, not just the job title. When in doubt, take advice from an OISC-regulated adviser or immigration solicitor.

3. Assigning a Defined CoS before UKVI approval is received. The fix: request the Defined CoS through the SMS and wait for the approval email before assigning. The system should prevent premature assignment, but sponsors sometimes mistake the request confirmation for approval.

4. Counting ineligible allowances toward the salary threshold. Certain allowances — for example, payments that are conditional on circumstance, or one-off bonuses — do not count toward the threshold. The fix: read the current UKVI guidance on salary calculations, or have a solicitor review the remuneration package before assigning.

5. Failing to update the SMS when the worker's role or salary changes post-arrival. The CoS is not a snapshot in time — your duty of care is ongoing. The fix: assign an internal process owner (typically an HR manager with Level 1 SMS access) who is responsible for monitoring and reporting changes within the required reporting windows.

6. Losing track of licence allocation. If you have used all your Undefined CoS allocation and do not request more, you cannot assign new CoS. The fix: build an allocation tracker into your HR calendar so you are never caught short when a new sponsored hire is imminent.

Illustrative Example: Assigning a CoS for an Accountant

This is an illustrative scenario only. All figures are indicative and should be verified against current official guidance.

An accounting firm in Manchester wishes to hire a qualified accountant from overseas. The role maps to SOC code 2421 (Chartered and Certified Accountants). The firm is a medium-sized employer.

• Step 1: The firm's Authorising Officer logs into the SMS and requests a Defined CoS, as the candidate is currently in India.
• Step 2: UKVI approves the request (processing times vary — see our sponsor licence application timeline guide for context on UKVI processing speeds more broadly).
• Step 3: The firm confirms the offered salary of £42,000 meets both the general threshold and the going rate for SOC 2421. It does.
• Step 4: The firm enters the worker's details exactly as shown in their passport, enters the SOC code, salary, start date, and Manchester office location.
• Step 5: The ISC is calculated for a three-year sponsorship at the medium employer rate. The firm pays this through the SMS payment portal.
• Step 6: The reference number is emailed to the candidate, who submits their Skilled Worker visa application within six weeks.

The firm posts its vacancy publicly before making the hire — since the role falls under a category where advertising requirements may apply, HR checked whether a Resident Labour Market Test (RLMT) obligation existed in their circumstances (note: while the formal RLMT was abolished for most Skilled Worker roles post-2020, certain sectors and roles have specific requirements, and this is worth verifying with a solicitor).

If you are recruiting for roles in the accountancy sector and want to understand what the candidate market looks like, our guide to accountant jobs in the UK with visa sponsorship gives a useful overview from the worker's perspective.

Your Ongoing Compliance Duties After the CoS Is Assigned

Many employers treat CoS assignment as the finish line. It is not. Once the worker is in the UK and employed, your compliance obligations are active and continuous.

What You Must Report to UKVI

Through the SMS, you are required to report:

• If the worker does not turn up for their first day of work.
• If the worker's employment ends before their visa expires (for any reason).
• Significant changes to their role, salary, or job title.
• Changes to their work location, particularly if they move to a site not listed on the CoS.
• Any absence from work that you cannot account for.

Most of these reports must be made within 10 working days of the event. Missing these windows is a reportable compliance failure.

Record-Keeping

You must retain copies of documents relevant to each sponsored worker — passport copies, visa evidence, right to work check records, payslips, and contact details. UKVI compliance officers can request these at any time, including during unannounced visits. Records should be kept for the duration of employment and typically for a period after employment ends — check current guidance for the precise retention period.

If You Stop Sponsoring a Worker

If a worker leaves your employment while on a Skilled Worker visa, you must report this through the SMS. UKVI will then notify the worker that their permission to stay is being curtailed. This is a legal requirement — it is not optional and it is not something you can delay because the situation is awkward.

A Note on Worker Protection

No legitimate employer charges a worker for their Certificate of Sponsorship, for the Immigration Skills Charge, or for the visa itself. These costs are the employer's responsibility. If you are working with a recruitment agency or immigration intermediary that suggests structuring the arrangement so the worker funds any part of their own sponsorship — through salary deductions, "loans," or any other mechanism — take immediate legal advice. Such arrangements may breach your sponsor duties and expose your organisation to significant consequences.

Workers who suspect they are being asked to pay for their own sponsorship should contact the Gangmasters and Labour Abuse Authority (GLAA) or the Employment Agency Standards Inspectorate. Employers should be aware that care sector and agricultural roles — where sponsored international recruitment is particularly common — receive heightened scrutiny. See, for example, our overview of care assistant jobs in the UK with visa sponsorship for context on the types of roles frequently sponsored in that sector.

When to Take Professional Advice

This guide is designed to give you a thorough working understanding of the Certificate of Sponsorship process. It is not immigration legal advice, and we are not immigration advisers. The following situations are ones where you should consult a solicitor regulated by the Solicitors Regulation Authority (SRA) or an adviser regulated by the Office of the Immigration Services Commissioner (OISC) before proceeding:

• You are unsure which SOC code applies to the role.
• The salary is close to — but not comfortably above — the threshold.
• The worker has an unusual immigration history (previous refusals, overstays, or complex nationality situations).
• You are considering whether allowances or benefits can be counted toward the salary.
• You have received a UKVI compliance visit notice or a licence suspension letter.
• You are sponsoring workers across multiple sites or through a contractor arrangement.

The cost of professional advice at the outset is almost always lower than the cost of unpicking a compliance problem after it has occurred.

Summary: The CoS Process at a Glance

• You must hold a valid, A-rated sponsor licence before assigning any CoS.
• Defined CoS (overseas applicants) require UKVI pre-approval; Undefined CoS (in-UK applicants) draw from your allocation.
• The CoS must accurately reflect the role, SOC code, and salary — both the general threshold and the going rate must be met.
• Pay the Immigration Skills Charge at the point of assignment (most roles).
• Give the reference number to the worker; they have three months to apply.
• Compliance duties continue throughout the worker's employment — report changes promptly through the SMS.
• Never charge workers for their sponsorship costs.