A Certificate of Sponsorship, or CoS, is how a licensed sponsor tells the Home Office it wants to sponsor a particular worker for a particular job. Sections S2 and S3 of Part 2 of the sponsor guidance set out the rules. This guide summarises them from the employer's side. It describes what the guidance requires; it does not say whether any worker or role meets the requirements of a route.
What a CoS is
A CoS is not a paper certificate. It is a database record, created in the sponsorship management system (SMS), confirming the details of the worker and the job (S2.2). GOV.UK says each certificate has its own number, which the worker uses to apply for their visa.
By assigning a CoS, the sponsor confirms that it wishes to sponsor the worker, is satisfied the worker can meet the immigration requirements, is eligible to sponsor them on that route, and agrees to the terms on the SMS (S2.3). Only Level 1 or Level 2 Users can assign one (S2.4).
Assigning a CoS does not guarantee the worker will get permission. They must meet all the requirements of the route they apply on (S2.5). Part 2 suggests talking to the worker about their current immigration status before assigning, because switching rules and time limits may affect their application (S2.6).
Defined and undefined certificates
There are two types. Defined certificates are for Skilled Workers applying for a visa from outside the UK. Undefined certificates are for Skilled Workers applying from inside the UK and for workers on every other route (S2.8). Undefined certificates come from the sponsor's annual allocation; defined ones are applied for one at a time (S2.9, S2.10). Assigning the wrong type is a ground on which the Home Office will normally revoke a licence (S2.11).
The fee
A fee is paid for each CoS assigned (S2.12). GOV.UK lists £525 per certificate on the Worker routes (except International Sportsperson) and £55 on the Temporary Worker routes, checked 3 Oct 2026. International Sportsperson certificates cost the higher amount when assigned for more than 12 months and the lower amount otherwise.
The sponsor must pay the CoS fee itself. It must not recoup any part of it, or associated administrative costs, from a Skilled Worker assigned a CoS on or after 31 December 2024, or from workers on the Global Business Mobility, Minister of Religion, International Sportsperson, Scale-up and Seasonal Worker routes assigned one on or after 9 April 2025 (S2.13). Doing so normally leads to revocation (S2.14). Skilled Worker and Senior or Specialist Worker certificates may also need the Immigration Skills Charge (S2.16). The cost calculator adds these up.
Rating restrictions
A sponsor normally needs an A-rating to assign a CoS. A B-rated sponsor can assign one only where the worker is extending on the same route, the sponsor assigned the CoS behind their last grant, and it is continuing to sponsor them (S3.3). No CoS can be assigned while a licence is suspended or dormant, or once it has ended through revocation (S3.4).
Who a CoS cannot be assigned to
An SMS User must not assign a CoS to themselves, their partner or a close relative. Part 2 says the Home Office will revoke the licence if that happens (S3.5). There is a narrow exception for UK Expansion Worker sponsors with a provisional rating. If an SMS User knows they have assigned a CoS to a partner or close relative of someone else working for the sponsor, they must add a sponsor note (S3.7).
What goes on a CoS
Paragraph S3.8 lists what a valid CoS must include, such as the route, the worker's personal and passport details, work addresses, average weekly hours, the job title and description, start and end dates, salary, occupation code, and whether an agent was used to find the worker. Section SK11.19 of the Skilled Worker guidance adds route-specific items, including the PAYE reference.
The job description must accurately reflect what the worker will do (S3.9). The sponsor is responsible for choosing the correct 4-digit SOC 2020 occupation code; Part 2 says UKVI cannot help with this (S3.30, S3.38). Using the wrong code can delay or lead to refusal of an application, and false or misleading information about skill or salary level leads to compliance action (S3.39). The role checker shows the published rules for each occupation code.
Timing: the 3-month window and start dates
The worker must use the CoS in an application within 3 months of it being assigned, and cannot apply more than 3 months before the start date on it (S3.12; GOV.UK). Part 2 asks sponsors to time recruitment so the worker is not left unable to make a successful application.
Once permission is granted, the worker should normally start within 28 days of the latest of the CoS start date, the "valid from" date on their eVisa or vignette, or the date they were told of the grant (S3.15). If they have not started by then, the sponsor must report a new start date with reasons, or stop sponsoring them, within 10 working days after the 28-day period (S3.16, S3.17).
The end date covers the intended period of sponsorship, up to the route's maximum. For Skilled Workers that is 5 years, or 4 years for new entrants (S3.24, S3.25).
Changing a CoS after it is assigned
While a CoS shows as "Assigned", a sponsor note can amend dates, salary or hours, fix a minor error such as a mistyped name, or add information (S3.42 to S3.44). A significant error, such as the wrong occupation code, the wrong route or more than one error in the worker's nationality, date of birth and surname, means withdrawing the CoS and assigning a new one (S3.45).
Common questions
Is a CoS a job offer?
No. It is a record confirming the sponsor's details of the job and the worker. A worker needs one before they can make a valid application on a sponsored route (Part 1, L1.4).
Can the worker pay the CoS fee?
No. The sponsor pays, and recouping the fee from the worker normally leads to revocation (S2.13, S2.14).
What happens if the worker does not use it in time?
The Skilled Worker guidance says that if the CoS was assigned more than 3 months before the application, UKVI may reject the application without considering it (SK11.15).
Where are the reporting duties after assigning a CoS?
In Part 3 of the guidance. The compliance checklist lists them with references.