What is a Certificate of Sponsorship (CoS) for a UK Visa?
Everything you need to know about the Certificate of Sponsorship — what it is, how to get one, the difference between Defined and Undefined CoS, and how to use it in your UK visa application.
What is a Certificate of Sponsorship?
A Certificate of Sponsorship (CoS) is a mandatory electronic record created by a UK-licensed employer that confirms they have offered you a specific job in the UK. Despite its name, it is not a physical certificate — it is a unique 12-character reference number held on the Home Office system. You cannot apply for a Skilled Worker visa (or most other work routes) without one. The CoS links you, your employer, and your specific job together in a single record that UKVI reviews as part of your visa application.
Key fact from GOV.UK
Only employers who hold an active sponsor licence issued by the Home Office can assign a Certificate of Sponsorship. If your employer cannot provide a valid CoS reference number, they are not legally permitted to sponsor you.
Who needs a Certificate of Sponsorship?
Skilled Worker visa applicants
The most common route. Your employer assigns a defined CoS once a confirmed job offer is in place and the role meets salary and skill-level requirements.
Health and Care Worker visa applicants
Doctors, nurses, and adult social care workers. The same CoS process applies but there are different salary requirements linked to NHS pay scales.
Global Business Mobility applicants
Workers seconded or transferred from an overseas entity to a UK branch. A CoS must still be assigned before the visa application opens.
Scale-up Worker visa applicants
For workers joining a qualifying fast-growth UK company. A CoS is required for the initial 6-month sponsored phase of this visa.
Senior or Specialist Worker (ICT) applicants
Previously known as Intra-Company Transfer. Employees of multinational companies being relocated to a UK office need a CoS from their UK entity.
You do not need a CoS if you are a British or Irish citizen, hold Indefinite Leave to Remain, or have the right to work in the UK without restrictions.
How to get a Certificate of Sponsorship
Secure a confirmed job offer
A CoS can only be assigned once you have a firm job offer — not speculatively. The role must be eligible for sponsorship (on the list of eligible occupations) and must pay at least the minimum salary threshold for your visa route.
Before you accept an offer
Confirm the employer's sponsor licence is Active on the current Home Office register. A licence can be revoked at any time. Search the employer on CHECKALL to see their current status before you commit.
Your employer logs in to the Sponsor Management System (SMS)
Only your employer can request and assign a CoS. The process takes place inside the Home Office's Sponsor Management System, which your employer's Authorising Officer or Level 1 User accesses. You will not log into this system yourself.
- Employer selects the correct visa route (e.g., Skilled Worker)
- Selects "defined" or "undefined" CoS type (most workers need a defined CoS)
- Fills in your personal details, job title, SOC occupation code, salary, and start date
- Submits the request — a reference number is generated immediately for defined CoS
Check the CoS details carefully
Your employer will share the 12-character CoS reference number with you. Before you begin your visa application, verify every detail is correct. Errors cannot be corrected mid-application — the CoS must be withdrawn and a new one assigned.
What to check on your CoS
Full name (must match your passport), date of birth, job title, SOC occupation code, annual salary (gross), start date, and the employer's licence number. Any mismatch with your passport or application can cause a refusal.
Use the CoS reference in your visa application
When you apply online for your Skilled Worker visa, you enter the CoS reference number in the relevant field. UK Visas and Immigration (UKVI) will automatically retrieve the linked record from the Home Office system. You do not need to upload the CoS as a document.
Apply online at GOV.UK
All Skilled Worker visa applications are submitted through the official GOV.UK online portal. Do not use third-party application services.
Wait for a decision
Once UKVI has your application, your identity documents, and your biometrics (if required), they will review your CoS alongside your other supporting evidence. The typical decision times are shown in the timeline section below — always allow extra time for complex cases.
How the CoS process works end-to-end
From job offer to visa decision, here is how the Certificate of Sponsorship fits into the overall Skilled Worker visa application process.
- 1
Employer assigns CoS on the SMS. Your employer logs into the Sponsor Management System, fills in your details, and assigns a defined CoS. You receive the 12-character reference number.
- 2
You apply online for your visa. Go to GOV.UK, start a Skilled Worker visa application, and enter your CoS reference. You'll also need to pay the application fee and the Immigration Health Surcharge (IHS).
- 3
Prove your identity. You will need to scan your passport using the UK Visas and Immigration: ID Check app or attend an appointment at a Visa Application Centre to provide biometric information.
- 4
UKVI reviews the application. UKVI checks your CoS, salary, English language evidence, and any other required documents. They may contact you or your employer for further information.
- 5
Decision and entry clearance. If successful, you'll receive a decision email with instructions to access your eVisa — a digital record of your immigration status. BRPs (physical cards) were replaced by eVisas from 31 October 2024. If you're outside the UK you'll get a short-stay vignette sticker to travel to the UK; your eVisa is then accessible via your UKVI account.
Typical timelines
Employer assigns CoS
CoS assignment
1–5 daysCan vary
Online visa application
Application submission
1–2 hoursOnline
Identity verification
Biometrics / ID Check app
1–14 daysCan vary
UKVI decision (outside UK)
Decision from abroad
Up to 3 weeksCan vary
UKVI decision (inside UK)
Decision in UK
Up to 8 weeksCan vary
Common mistakes to avoid
Accepting an offer before verifying the sponsor licence
An employer can lose their licence between the time you receive an offer and when your CoS is assigned. Always check their current status on the Home Office register before committing.
Starting your visa application with wrong CoS details
Details on the CoS — particularly your name, date of birth, and salary — must exactly match your passport and supporting documents. A discrepancy requires the CoS to be withdrawn and reissued, delaying your application.
Applying before your CoS is assigned
You must have a valid CoS reference number before you can submit your visa application. Do not start the online application until you have this number confirmed in writing from your employer.
Confusing a CoS with a job contract
A CoS is an administrative record on the Home Office system, not your employment contract. You need both — the CoS for your visa application and a signed employment contract to evidence your role.
Frequently asked questions
Ready to find a licensed UK visa sponsor?
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