The UK Certificate of Sponsorship system has two types -- Defined and Undefined -- and using the wrong one is a surprisingly common error that costs employers time and money. The distinction is simple once you understand it, but the consequences of getting it wrong include wasted CoS fees, delayed visa applications, and frustrated candidates. This guide explains when to use each type and how the allocation process works.
The Core Distinction
When to Use Defined CoS
Defined CoS Scenarios
Your candidate is currently outside the UK and will apply for their visa from abroad
Your candidate is in the UK as a visitor but cannot switch from within the UK
Your candidate is outside the UK and will enter on the Skilled Worker visa after it is granted
Defined CoS requires a formal allocation request to UKVI. They review the role details, SOC code and salary before releasing the allocation. This adds 1-5 working days to the process but provides a degree of pre-validation.
When to Use Undefined CoS
Undefined CoS Scenarios
Your candidate is already in the UK on a Student visa and switching to Skilled Worker
Your candidate is on a Graduate visa and switching
Your candidate is extending an existing Skilled Worker visa with your company
Your candidate is switching from another visa category that allows in-country switching
Undefined CoS are drawn from your annual allocation and can be assigned immediately through the SMS without UKVI pre-approval. This makes the process faster but means any errors are only caught at the visa application stage.
Requesting Additional Defined CoS Allocations
If you need more Defined CoS than your current allocation allows, you can request additional allocations through the SMS. The request must include:
What to Include in an Allocation Request
The number of additional CoS needed
The SOC code and job title for each role
The salary for each role
Justification for why the roles cannot be filled by settled workers
The Cost Implications
Both types cost GBP 525 per CoS. The difference is not in cost but in process. A Defined CoS that is allocated and then cancelled (because the candidate withdrew) still costs GBP 525 -- the allocation may be returned but the fee is not. This makes accurate candidate pipeline management important for overseas hires.
Common Errors
Defined/Undefined Mix-Up Errors
Using Undefined for an overseas worker: The visa application will be refused because the CoS type does not match the application route.
Using Defined for an in-country switcher: Unnecessarily delays the process by requiring an allocation request that was not needed.
Requesting too many allocations: UKVI may question why you need 20 Defined CoS allocations if you have only sponsored 2 workers historically. Keep requests proportionate to your genuine hiring plan.
How Recruitroo Handles CoS Type Selection
Recruitroo automatically determines the correct CoS type based on the candidate location and visa status. Our platform requests Defined allocations for overseas candidates and draws from Undefined allocations for in-country switchers -- eliminating the mix-up risk entirely.
Unsure whether your candidate needs a Defined or Undefined CoS?
Send us the candidate details and current location. We will confirm the correct CoS type and handle the assignment.
Get a QuoteSee Client StoriesThis guide reflects UK CoS rules as of May 2026. UKVI CoS allocation processes are subject to change.