Programme and scope
The programme must be approved by ICAO and the unit must sit within the programme's eligible scope.
Aviation and carbon markets
CORSIA-eligible emissions units
CORSIA Eligible Emissions Units are carbon credits that meet ICAO eligibility rules for a specified compliance period. Aeroplane operators cancel eligible units to meet their final offsetting requirements. Programme approval alone does not make every credit eligible.
The short answer
What is a CORSIA Eligible Emissions Unit?
The formal term is a CORSIA Eligible Emissions Unit, or CEEU. Each unit represents one metric tonne of CO2e reduced or removed, but eligibility depends on the complete unit record, not simply the name of the crediting programme.
Dates and exclusions
Activity start dates, crediting periods, vintages and any exclusions in ICAO's current document must all be checked.
Host-country requirements
Units from 2021 onward have specific requirements relating to host-country attestations and double-counting safeguards.
Operator pathway
How operators meet a CORSIA obligation
CORSIA operates alongside direct aviation measures. An operator's final offsetting requirement is determined through the scheme before eligible units are cancelled.
Monitor and verify
Measure and report covered international aviation emissions in line with CORSIA requirements.
Reduce where possible
Use operational improvements, technology and eligible fuels to reduce emissions and offsetting requirements.
Acquire eligible units
Select units that meet the programme, methodology, date, exclusion and authorisation rules.
Cancel and report
Cancel enough CEEUs to meet the final requirement and retain the supporting registry evidence.
Due diligence
Eligibility depends on the complete unit record
A programme name is only the start. Buyers should validate the exact unit against the current ICAO eligibility document and the relevant programme registry before purchasing.
ICAO-approved programme and applicable scope
Eligible activity and methodology
Activity start date and crediting period
Unit vintage and issuance details
Any programme-specific exclusions
Registry status and unique serial numbers
Host-country attestation requirements
Evidence needed for cancellation and reporting
Project evidence
Eligible units originate in real projects
Carbon units are backed by measurable, independently verified outcomes. Eligibility for CORSIA adds a defined compliance screen, but buyers should still understand the underlying project, its monitoring approach and its wider environmental and community effects.
Current eligibility
ICAO determines which programmes and units qualify
ICAO Council approval follows assessment against the CORSIA Emissions Unit Eligibility Criteria. As of the April 2026 edition, ten programmes have fully eligible scope for the 2024-2026 first phase, each subject to the conditions and exclusions in ICAO's detailed document.
- American Carbon Registry
- Architecture for REDD+ Transactions
- BioCarbon Fund Initiative for Sustainable Forest Landscapes
- Climate Action Reserve
- Forest Carbon Partnership Facility
- Global Carbon Council
- Gold Standard
- Isometric
- Thailand Voluntary Emission Reduction Programme
- Verified Carbon Standard, including the applicable jurisdictional scope
Current to the ICAO April 2026 edition. Eligibility is conditional at unit level and the official ICAO document should always be checked before a transaction. Other programmes may have conditional or different-period status.
Check the current ICAO eligibility documents →Host-country accounting
How authorisation supports credible use
For relevant units, host-country action helps prevent the same mitigation outcome being counted both towards CORSIA and the host country's Paris Agreement target. The evidence pathway is not always a single linear sequence, so the programme's assurance arrangements must be reviewed in context.
Letter of Authorisation
A host government may authorise specified mitigation outcomes for CORSIA use and commit to the necessary accounting treatment.
Corresponding adjustment
The host country applies an accounting adjustment so the authorised mitigation outcome is not also counted towards its own NDC achievement.
Reporting and assurance
Biennial Transparency Reports and programme-level guarantees or assurance arrangements can provide evidence of authorisation and accounting.
Use cases
Compliance eligibility is different from voluntary use
Voluntary carbon credit use
Organisations choose credits voluntarily as part of a wider climate strategy. Quality, claims and procurement requirements depend on the buyer's purpose and the frameworks it follows.
CORSIA compliance use
Aeroplane operators cancel units to meet a regulatory offsetting requirement. The exact units must satisfy ICAO's programme, scope, date and host-country requirements.
Buyer questions
Questions to ask before purchasing
A careful review should be based on the current ICAO documents and the exact serialised units being offered.
Which compliance period are the units intended for?
Is the programme fully eligible for that period?
Do the activity and methodology fall within scope?
Are the start date, crediting period and vintage eligible?
What host-country attestation applies?
How is double counting addressed?
What registry evidence will accompany the transaction?
Who will support cancellation and compliance records?
This page provides general information and is not legal, regulatory or aviation compliance advice. Buyers should validate requirements for their circumstances with the relevant State authority and professional advisers.
CO2balance support
Prepare a CORSIA credit enquiry
CO2balance can help buyers review project evidence, discuss current unit options and understand the transaction and registry records to request. An initial enquiry is most useful when it includes:
- Period and volume
- The intended compliance period, the quantity required and your procurement timetable. If the volume is provisional, say which assumptions still need confirmation.
- Units and evidence
- Any proposed programme, project, methodology or vintage, together with registry links and available host-country documentation. You can also enquire before selecting a project.
- Cancellation and records
- Your required cancellation timing, reporting deadlines and the documentation your procurement and assurance teams need to retain.
Include your compliance period and evidence requirements in the enquiry message.
Eligibility and availability must be checked for the exact units. An initial discussion does not confirm a credit's CORSIA eligibility. Formal obligations and regulatory sign-off remain with the operator, its State authority and its appointed advisers.
Frequently asked questions
CORSIA carbon credit questions
What does CORSIA stand for?
CORSIA is the Carbon Offsetting and Reduction Scheme for International Aviation, developed by the International Civil Aviation Organization.
What is a CORSIA Eligible Emissions Unit?
It is an emissions unit that satisfies the ICAO eligibility rules for a specified CORSIA compliance period and can be cancelled by an operator towards its final offsetting requirement.
Does programme approval make every unit eligible?
No. The unit must also satisfy the approved scope, activity, methodology, dates, exclusions and applicable host-country requirements in ICAO's current documents.
How much does one eligible unit represent?
One eligible emissions unit represents one metric tonne of carbon dioxide equivalent reduced or removed.
What is a Letter of Authorisation?
It is a host-country authorisation covering specified mitigation outcomes and their intended international use. Its wording and scope should be checked against the relevant programme and CORSIA requirements.
What is a corresponding adjustment?
It is an accounting adjustment used to prevent an authorised mitigation outcome being counted both by the international user and towards the host country's own Paris Agreement target.
Are CORSIA units the same as CCP-labelled credits?
No. CORSIA eligibility relates to aviation compliance, while the CCP label is a voluntary-market integrity benchmark. A unit may meet both frameworks if it satisfies each set of requirements.
Can CO2balance confirm my compliance obligation?
CO2balance can support project and unit diligence. The operator's obligation and formal compliance position should be confirmed with its State authority and professional advisers.
Primary sources: ICAO, CORSIA Eligible Emissions Units, including the April 2026 eligibility document and programme summary table. Eligibility document checked 1 October 2026. Aviation image by Sevcan Alkan via Unsplash, used under the Unsplash License.
Need help assessing CORSIA-eligible units?
Share the intended compliance period, volume and timing, together with any unit or project information you already have. Our team can discuss the evidence and next steps for your requirement.