Certificates of Sponsorship for UK Employers
A Certificate of Sponsorship (CoS) is the electronic sponsorship record a licensed employer assigns to a worker through the Sponsorship Management System. It records details of the worker and the job and represents the sponsor's confirmation that it wishes to sponsor that person and has carried out the relevant sponsorship checks. A CoS does not itself grant immigration permission and does not guarantee that the worker's application will succeed — employers must use the correct CoS type, remain within their allocation where one applies, pay the applicable charges and ensure the information supplied is accurate.
On this page
- What is a CoS?
- What assigning means
- Does it guarantee a visa?
- Who can assign one?
- Pre-assignment checks
- Defined & Undefined
- CoS allocation
- How allocation is decided
- What is a CoS year?
- Reducing an allocation
- Requesting more CoS
- Unused CoS
- Annual renewal
- Manual renewal
- How much a CoS costs
- Charging the worker?
- CoS fee vs ISC
- If the rules aren't followed
- CoS lifecycle
- CoS Allocation Planner
- How ENS can assist
- FAQs
In brief
- A Certificate of Sponsorship (CoS) is the electronic sponsorship record an employer assigns to a worker through the SMS.
- Assigning a CoS is a serious step — it does not guarantee the worker’s visa, and only authorised Key Personnel can do it.
- CoS come in Defined (entry-clearance Skilled Workers) and Undefined types, drawn from an annual allocation.
- Before assigning, the employer must check the role, salary and worker details are correct.
What is a Certificate of Sponsorship?
Before a worker can make a successful application under a sponsored Worker or Temporary Worker route, the sponsor must assign a valid CoS. A CoS is not a paper certificate — it's a database/electronic record, created and assigned through the Sponsorship Management System (SMS), linked to the worker and the job being sponsored. It has a unique reference number issued by the sponsor through the SMS, confirming details of the sponsored job.
A Certificate of Sponsorship is not a physical certificate. It's an electronic sponsorship record created through the Sponsorship Management System and linked to the worker and sponsored role.
For how the worker uses the CoS in a Skilled Worker application, see the applicant-side page: Certificate of Sponsorship (applicant) →
What does assigning a CoS mean for the sponsor?
By assigning a CoS, the licensed sponsor confirms that it wishes to sponsor the worker; is satisfied that the worker can meet the relevant immigration requirements; is eligible to sponsor the worker on the route concerned; and agrees to comply with the terms and conditions stated through the SMS. Before assigning, the sponsor must also consider matters including whether the role is eligible, whether the worker will be paid appropriately, whether the worker is eligible, and any additional requirements applying to the route.
Assigning a CoS is a sponsorship declaration, not simply generating a reference number. The employer is confirming that it wishes to sponsor the worker and has considered the applicable sponsorship requirements.
Role issues: genuine role · occupation codes · salary requirements.
Does a Certificate of Sponsorship guarantee the worker's visa?
No. The sponsor guidance expressly states that assigning a CoS does not guarantee that the worker will be granted entry clearance or permission — the worker must still meet all of the immigration requirements applying to their route. The employer should satisfy itself, before assignment, that the worker appears able to meet the relevant requirements.
CoS assigned does not mean visa approved. Sponsorship supports the worker's application, but the Home Office separately decides whether the individual meets the immigration requirements.
→ Applicant route: Skilled Worker visa.
Who can assign a Certificate of Sponsorship?
A CoS can only be assigned by a person who has SMS access as either a Level 1 User or a Level 2 User. The Key Personnel guidance sets different functions and restrictions for those users — Level 2 access is more limited than Level 1 access.
→ Sponsor Licence Key Personnel · Sponsorship Management System.
What must an employer check before assigning a CoS?
Before assigning sponsorship, the sponsor should consider whether it holds the relevant Sponsor Licence; whether the role is eligible; whether applicable pay and conditions are satisfied; whether the worker appears eligible under the relevant route; whether any route-specific requirements have been completed; and whether the employment/sponsorship relationship is permissible. The guidance also advises discussing the worker's current immigration status, because switching rules or route-specific maximum periods can affect the application.
Worker's immigration position considered
Switching & time-limit issues.
Completing these preparation checks does not confirm that the worker qualifies for immigration permission.
Defined and Undefined Certificates of Sponsorship
There are two types of CoS. This page covers only the top-level distinction — the detailed decision rules are on the Defined vs Undefined page.
Defined CoS
Used for Skilled Workers applying for entry clearance from outside the UK. There's no annual allocation of Defined CoS — a separate Defined CoS application is made when one is needed.
Undefined CoS
Used for Skilled Workers applying for permission to stay from within the UK, and for workers on all other sponsored Worker/Temporary Worker routes (entry clearance, permission to enter or stay). Assigned from the sponsor's annual allocation.
For Skilled Worker sponsorship, location of application matters — and using the wrong type is serious. A worker applying from outside the UK for entry clearance requires a Defined CoS; a Skilled Worker applying for permission to stay from within the UK uses an Undefined CoS. The Home Office will normally revoke the licence if a sponsor assigns a Defined CoS for a job other than the one in the Defined CoS application, or assigns an Undefined CoS where a Defined CoS is required.
→ Defined vs Undefined CoS (decision rules) · assigning a CoS (mechanics).
What is a CoS allocation?
When applying for a Sponsor Licence, the organisation is asked to estimate how many Undefined CoS it expects to assign during its first year for the applicable routes. The sponsor must justify that request and the Home Office may ask for further information before deciding the allocation. If the licence is granted, the Home Office tells the organisation what CoS allocation it has for the relevant year.
An allocation is not a finding that every future worker or vacancy is suitable for sponsorship. It simply determines how many applicable Undefined CoS the sponsor is authorised to assign during that allocation period, subject to all sponsorship rules.
→ Application-stage estimate: application process.
How does the Home Office decide a CoS allocation?
When setting the allocation, the Home Office may consider factors including the recruitment agents the sponsor uses and any links to previous immigration abuse; the sponsor's previous dealings/compliance history; the number of workers the organisation employs; the type of business; the extent of its business activities; how long it has been trading; and specific UK Expansion Worker factors where relevant. The same broad considerations can apply to decisions on Skilled Worker Defined CoS applications.
The Home Office may allocate fewer CoS than requested, or set the allocation at zero — for reasons including previous non-compliance; insufficient justification for the number requested; the claimed sponsorship need not being credible given the organisation's circumstances; concerns the organisation can't offer work satisfying the eligible-role requirements; or uncertainty about whether or when it will actually need workers.
A CoS allocation request should reflect a credible recruitment need. The Home Office can reduce the number requested or set the allocation to zero where the request is insufficiently justified or inconsistent with the organisation's circumstances.
What is a CoS year?
Once the Home Office sets an annual CoS allocation, the CoS are placed in the sponsor's SMS account and are available for the applicable CoS year (also called the allocation year). For most current sponsors, a CoS allocation operates over a 12-month allocation year (current general period, as at August 2026 — confirm against the latest sponsor guidance). Historic transitional rules apply to some licences converted from the former Tier 2 system.
Historic Tier 2 licence allocation arrangements +
Some licences converted from the former Tier 2 system have special historic allocation timing that differs from the ordinary 12-month year. If your licence pre-dates the current system, check the transitional arrangements in the current SMS guidance rather than assuming the standard allocation year applies. SMS guidance →
Can the Home Office reduce a sponsor's CoS allocation?
Yes. The Home Office can reduce a sponsor's allocation or set it to zero where circumstances change — for example the organisation downsizing, or the Home Office considering that the sponsor poses a threat to immigration control, including following compliance action. Reducing a CoS allocation is also one of the compliance measures available to the Home Office.
A CoS allocation is not guaranteed for the whole life of the Sponsor Licence. The Home Office can reduce or remove allocation where the sponsor's circumstances or compliance position justify it.
→ licence ratings · compliance checks.
Can an employer request more Certificates of Sponsorship?
Where the sponsor believes its remaining annual allocation won't be sufficient for the rest of its CoS year — or where its allocation was previously set to zero — it can apply through the SMS to increase the allocation. The sponsor must provide reasons and the Home Office may request supporting evidence.
An additional CoS allocation is not automatic. The sponsor must explain why more CoS are required and may be asked to support the request with evidence. The click-by-click SMS process sits in the separate SMS manuals — see SMS.
What happens to unused CoS at the end of the allocation year?
Annual CoS allocations need to be renewed while the Sponsor Licence remains valid. Any unused CoS remaining at the end of the CoS year are removed from the SMS account — they cannot be carried forward into the next allocation year.
Unused annual CoS do not roll over. CoS remaining at the end of the allocation year are removed rather than carried into the next CoS year.
How are annual CoS allocations renewed?
At the end of a CoS year, the sponsor will either receive an automatic allocation for the next year, or need to make a manual follow-on allocation request through the SMS. Automatic annual allocation requires all of the following: the licence is A-rated; the current annual CoS allocation is marked active in the SMS; and the sponsor is licensed on an eligible route.
The following routes are currently excluded from automatic annual allocation (as at August 2026 — confirm): Seasonal Worker; Secondment Worker; Service Supplier; and UK Expansion Worker.
Where automatic renewal applies, the following year's allocation equals the number of CoS actually assigned during the previous CoS year — not necessarily the previous maximum allocation. For example, if 15 were allocated and 10 were assigned, the next automatic allocation would be 10.
Skilled Worker caveat. For Skilled Worker, automatic allocation covers Undefined CoS only — Defined CoS continue to be requested individually as needed.
When is a manual allocation renewal needed?
Where the sponsor doesn't satisfy the automatic-renewal criteria, it must make a manual allocation request through the SMS for the next CoS year. A manual request can currently be submitted up to 3 months before the end of the CoS year (current window, as at August 2026 — confirm against the latest sponsor guidance).
The detailed technical management sits in the SMS manuals (separate source) — see SMS.
How much does a Certificate of Sponsorship cost?
The sponsor must pay a fee for each CoS it assigns. If the correct fee isn't paid, the Home Office may cancel the CoS, and the worker's application relying on that CoS may consequently be rejected or refused.
Certificate of Sponsorship fee
Current £ figure not shown — the sponsor guidance confirms a fee is payable for every CoS but directs employers to the current UK visa fees. Confirm on GOV.UK →
Fees can differ by route
The CoS fee may vary by sponsorship route — check the current GOV.UK visa fees for the specific route rather than assuming a single figure.
Can the CoS fee be charged to the worker?
The sponsor is responsible for paying the CoS fee. Under the current guidance, the sponsor must not recoup or attempt to recoup any part of the CoS fee or associated administrative costs from a sponsored worker where the relevant assignment date/rule applies. The guidance expressly identifies Skilled Worker CoS assigned on or after 31 December 2024, and specified other routes where the CoS is assigned on or after 9 April 2025 (including Global Business Mobility routes, Minister of Religion, International Sportsperson, Scale-up and Seasonal Worker). If the sponsor breaches the applicable prohibition, the Home Office states that it will normally revoke the Sponsor Licence.
Do not automatically pass the CoS fee to the sponsored worker. The current guidance prohibits recovery of the CoS fee and associated administrative costs from workers in the specified routes and circumstances, with Sponsor Licence revocation identified as the normal consequence of breach.
Is the Immigration Skills Charge the same as the CoS fee?
No. The CoS fee is the charge associated with assigning a Certificate of Sponsorship. Separately, sponsors of Skilled Workers and Senior or Specialist Workers may also need to pay the Immigration Skills Charge (ISC) when assigning a CoS, subject to applicable exemptions.
| Charge | What it relates to | Detailed owner |
|---|---|---|
| CoS fee | Assignment of the Certificate of Sponsorship | This page / assignment page |
| Immigration Skills Charge | Additional charge applying to specified sponsorship | ISC page |
→ Immigration Skills Charge (rates, exemptions, refunds).
What happens if the sponsor does not follow the CoS rules?
Failure to follow the CoS rules can result in Home Office action including reducing or removing the number of CoS available; downgrading the Sponsor Licence; suspending the licence; or revoking the licence. Serious examples include assigning the wrong type of Skilled Worker CoS in the circumstances described above. Reducing a CoS allocation is also among the compliance measures available to the Home Office.
CoS errors can affect the Sponsor Licence itself. The Home Office can take action not only against an individual CoS but against the sponsor's allocation or licence where sponsorship rules are not followed.
→ ratings · suspension · revocation.
Certificate of Sponsorship lifecycle for employers
- Confirm the correct Sponsor Licence route — the organisation must hold a valid licence for the route it wants to sponsor on. → licence types
- Check the role and sponsorship arrangement — review whether the proposed work is appropriate for sponsorship. → genuine role
- Consider the worker's immigration position — whether they appear able to meet the route requirements, and any switching/time-limit issues.
- Identify the correct CoS type — for Skilled Worker, decide Defined or Undefined. → Defined vs Undefined
- Check CoS availability — for Undefined, confirm sufficient allocation; for Defined, use the separate request process.
- Assign the CoS through SMS — an authorised Level 1 or Level 2 User assigns the record. → assigning a CoS
- Pay the relevant sponsor charges — the applicable CoS fee and, where relevant, the ISC. → ISC
- Continue sponsor compliance — monitor the worker, report relevant changes and retain the required records. → sponsor duties
CoS Allocation Planner
Tell the planner what you're trying to do and it will point you to the area of the CoS rules to review. It does not recommend a number of CoS, and it does not confirm that a role or worker qualifies.
This planner organises which part of the CoS rules to review. It does not recommend a number of CoS, does not confirm any allocation will be granted, and does not confirm that a role or worker meets the immigration requirements.
How ENS can assist with Certificates of Sponsorship
We advise and assist sponsors with matters including identifying whether a Defined or Undefined CoS should be reviewed; assessing employer-side CoS requirements before assignment; reviewing the proposed role and sponsorship arrangement; checking information prepared for CoS assignment; advising on CoS allocation issues; assisting with requests for additional allocation; advising on CoS-related compliance concerns; considering whether the Immigration Skills Charge applies; and helping sponsors understand their continuing reporting and record-keeping duties. The licensed sponsor, through its authorised SMS users, assigns CoS — we don't issue Certificates of Sponsorship and can't guarantee that a CoS or a worker's visa will be approved.
Certificate of Sponsorship advice for employers
The work required depends on whether the employer needs advice on CoS type, allocation, role review, assignment preparation or a wider sponsorship issue. We agree the scope and a fixed fee in writing before any work begins.
Discuss a Certificate of Sponsorship issue
Frequently asked questions
What is a Certificate of Sponsorship? +
A Certificate of Sponsorship is an electronic sponsorship record created through the Sponsorship Management System. It confirms details about the worker and the job the sponsor intends to sponsor them for. It is not a physical paper certificate.
Does assigning a CoS guarantee that the worker will get a visa? +
No. The sponsor guidance expressly states that assigning a CoS does not guarantee entry clearance or permission. The worker must separately meet all of the requirements of the immigration route.
Who can assign a Certificate of Sponsorship? +
A CoS can only be assigned through the SMS by an authorised Level 1 or Level 2 User.
What is the difference between Defined and Undefined CoS? +
Defined CoS are used for Skilled Workers applying for entry clearance from outside the UK. Undefined CoS are used for Skilled Workers applying from within the UK and for workers on the other sponsored Worker and Temporary Worker routes. See Defined vs Undefined.
Can an employer ask for more CoS during the year? +
Yes. Where the sponsor expects its remaining annual allocation to be insufficient, or its allocation was previously set to zero, it can request an increase through the SMS. It must give reasons and may be asked for supporting evidence.
Do unused Certificates of Sponsorship carry over to the next year? +
No. Unused CoS in the annual allocation are removed at the end of the CoS year and cannot be carried forward into the next allocation year.
Sponsoring workers, or thinking about it? Get a fixed-fee quote for your sponsor licence and Certificate of Sponsorship work.
Get a fixed-fee quoteRelated guidance
Applicant-side: CoS for applicants · Skilled Worker visa · Health & Care Worker. Compliance: sponsor duties · reporting · record keeping.
Disclaimer. This page provides general employer guidance on Certificates of Sponsorship. A CoS does not itself establish that a worker or role qualifies under an immigration route, and assignment does not guarantee that an immigration application will be granted. CoS fees and allocation periods are volatile and should be verified against the current GOV.UK source. Sources: Home Office sponsor guidance — Part 2 & Part 3, and the sponsor guidance glossary — confirm the current version on GOV.UK.
Source basis: the UK Immigration Rules and the Home Office sponsor guidance for Workers and Temporary Workers (sponsor a worker, and sponsor duties and compliance) published on GOV.UK. Rules and guidance change; confirm the current version on GOV.UK before relying on it.
Check the CoS before you assign it
A Certificate of Sponsorship is the employer's formal sponsorship record for a worker and job. Before assignment, the sponsor should confirm that it holds the appropriate licence, is using the correct CoS type, has sufficient allocation where required and has checked the relevant role, worker and route requirements.