A Certificate of Sponsorship (CoS) is a unique reference number a UK sponsor assigns through the Sponsor Management System (SMS) for a specific worker, role, and visa application. Defined CoS for entry-clearance (visa from overseas) are allocated annually to sponsors in batches. Undefined CoS for in-country switches are issued on demand from the sponsor''s rolling allocation.

CoS assignment is one of the highest-stakes routine tasks in sponsor licence administration. The data entered into SMS becomes the visa''s legal foundation. Errors are hard to correct after issue.

Defined vs Undefined CoS

Defined CoS

Used for: applicants outside the UK applying for Entry Clearance.
Allocation: each sponsor receives an annual allocation. Run out, you can request more via SMS.
Lead time: typically allocated in 1-3 working days on request.
Validity: must be used within 3 months of issue.
CoS fee: £239 (2024/25).

Undefined CoS

Used for: applicants already in the UK switching from another visa to Skilled Worker.
Allocation: from the sponsor''s rolling allocation (not annual batch).
Lead time: assigned immediately on SMS.
Validity: must be used within 3 months of issue.
CoS fee: £239 (2024/25).

Sponsors typically have a small allocation of each type. New sponsors may receive a starter allocation (e.g. 5 of each); larger sponsors negotiate higher allocations based on demonstrated need.

Before you assign

Confirm in writing:

The role

SOC code (matching the actual duties — see our SOC codes guide).
Role title.
Detailed job description.
Reporting line.

The salary

Annual gross salary in £.
Confirm it meets the higher of £38,700 or the going rate for the SOC code.
If relying on tradeable points (new entrant, PhD), confirm the relevant lower threshold applies.

The hours and pattern

Standard hours per week.
Work pattern (e.g. 9-5 Monday-Friday).
Note any flexibility / hybrid arrangements.

The work location(s)

Primary work address.
Any secondary sites where the worker will regularly work.
If remote/hybrid, primary location for sponsorship purposes.

The dates

Proposed start date — typically 4-8 weeks after CoS assignment to allow for visa processing.
End date — typically up to 5 years from start.

The worker

Full legal name (as on passport).
Date of birth.
Nationality.
Passport number.
Existing UK visa status (for Undefined CoS).
Whether they hold any qualifications relevant to the role (PhD relevance for tradeable points).

The cost confirmation

Immigration Skills Charge calculation (£364/year for small/charitable sponsors; £1,000/year for medium/large).
CoS fee (£239).
Visa application fee (typically paid by the worker, sometimes by employer).
Immigration Health Surcharge (£1,035/year, prepaid for the whole visa).

Step-by-step SMS process

Log into SMS as a Level 1 User.
Navigate to "Workers" → "Sponsored workers" → "Assign CoS".
Select CoS type — Defined or Undefined.
Enter worker details — name, date of birth, nationality, passport.
Enter role details — SOC code, role title, duties description (key duties, 200-400 characters).
Enter salary and hours — annual gross salary, hours per week.
Enter work location(s) — primary and any additional sites.
Enter start and end dates.
Pay the Immigration Skills Charge upfront — for the full duration of sponsorship, by debit card or BACS. (You get a partial refund if sponsorship ends early.)
Pay the CoS fee — £239.
Confirm and submit.

The CoS reference number is generated. Pass it to the worker for their visa application.

Common assignment errors

Wrong SOC code

The SOC code on the CoS must match the duties. Choosing a higher-skill code to meet the threshold while the actual duties are at a lower level is a recipe for refusal — or worse, post-issue licence problems.

Salary below going rate

The system blocks salaries below the threshold, but you can sometimes enter a salary that''s above the general £38,700 floor but below the SOC-specific going rate. The visa will then be refused.

Hours and salary mismatch

If you enter 35 hours/week but the salary is so low it implies less than minimum wage for those hours, the application has issues.

The work location on the CoS must be a location the sponsor licence covers. If the worker will be based at a different site that''s not on the licence, update the licence first.

Spelling and passport detail errors

Name spelled differently from the passport, wrong DOB, wrong passport number — all cause visa application delays or refusals. Verify before submitting.

Forgetting tradeable points

If the worker qualifies for new-entrant, PhD, or STEM PhD discount, claim it on the CoS. You can''t add it later.

After assignment

Pass the CoS to the worker

The CoS reference is a number. The worker uses it on their visa application. They don''t receive a paper certificate.

Monitor the visa application

The worker applies for the visa using the CoS. Processing typically takes:

From overseas: 3-6 weeks (faster with priority service).
In-country switching: 8 weeks (faster with priority).

Review every CoS you''ve assigned in the past 12 months. Verify SMS data matches the actual employment (salary, role, location, duties).
Audit your current allocations of Defined and Undefined CoS. If you''re running low and have hires planned, request more in advance.
Brief HR / hiring managers on what you need from them before assigning a CoS — the role description, the SOC code research, the right-to-work check plan.

Certificate of Sponsorship: how to assign one