CORSIA eligible carbon credits: what airlines can use

CORSIA (Carbon Offsetting and Reduction Scheme for International Aviation) eligible carbon credits are not just ordinary voluntary offsets. For the wider scheme route map, use the CORSIA aviation carbon market guide. Eligible credits are emissions units from programmes approved by ICAO (International Civil Aviation Organization), within specific eligibility scopes, that airlines can cancel to meet CORSIA offsetting obligations. This guide explains what makes a credit CORSIA eligible and what buyers should check before relying on one.

What does CORSIA eligible mean?

A carbon credit is CORSIA eligible only if it is covered by the official ICAO (International Civil Aviation Organization) document CORSIA Eligible Emissions Units for the relevant compliance period and scope. It must come from an approved emissions unit programme, meet the approved vintage and activity limits, and satisfy any additional conditions attached to that programme's approval.

This matters because carbon credit eligibility is not decided by an airline, broker, project developer or individual state. ICAO makes eligibility decisions through the ICAO Council, considering recommendations from the Technical Advisory Body.

Eligible emissions units explained

An eligible emissions unit is a unit that an aircraft operator can cancel to meet CORSIA offsetting requirements. The operator's obligation is calculated by the state to which it is attributed. The operator then cancels CORSIA eligible emissions units equal to its final offsetting requirement for the compliance period.

The key word is eligible. A credit may be real, verified and tradable in the voluntary market but still not be eligible for CORSIA. Conversely, CORSIA eligibility does not remove the need for project-level diligence. It is a scheme eligibility filter, not a complete quality guarantee.

How ICAO assesses programmes

ICAO assesses emissions unit programmes against CORSIA Emissions Unit Eligibility Criteria. These include programme design elements and carbon offset credit integrity criteria. The aim is to ensure environmental and social integrity at the programme level.

The Technical Advisory Body reviews programmes and makes recommendations. The ICAO Council then decides which programmes and units are approved. ICAO publishes the outcome in the CORSIA Eligible Emissions Units document, which is updated over time.

Programme eligibility vs project eligibility

One common mistake is to assume that if a programme is listed, every credit from that programme is eligible. That is not how CORSIA works. ICAO approvals often include limitations by vintage, activity type, methodology, country, crediting period or compliance period.

For example, a registry may be approved for the 2024 to 2026 compliance period, but only for certain units and with specific conditions. Buyers need to check both the programme approval and the unit-level details.

Article 6 and corresponding adjustments

CORSIA sits in a carbon market shaped by the Paris Agreement. Article 6 is the part of the Paris Agreement dealing with international cooperation and carbon market transfers. A central issue is double counting: the same emissions reduction should not be counted by both the host country and the buyer for separate climate targets.

Corresponding adjustments are accounting adjustments used to avoid that double counting. For CORSIA, this is particularly important because international aviation is using emissions units generated in host countries. Airlines, brokers and project developers increasingly need to understand whether units have the right host-country authorisation and accounting treatment for CORSIA use.

CORSIA eligible vs high quality

CORSIA eligibility and credit quality overlap, but they are not identical. Eligibility asks whether a unit can be used for CORSIA compliance. Quality asks whether the credit is additional, measurable, permanent, independently verified, not double-counted and appropriate for the claim.

An airline can buy a CORSIA eligible unit and still ask deeper quality questions. Is the project avoidance or removal? Is there reversal risk? Are local communities affected? Is the baseline credible? Has the methodology been criticised? Does the unit fit the airline's broader climate strategy?

How to triage a CORSIA credit before procurement

A practical triage starts with three gates. First, eligibility: does the unit appear within the current ICAO eligibility scope for the relevant compliance period? Second, evidence: can the seller provide project documents, serial numbers, vintage, methodology and registry status? Third, claim risk: would the airline be comfortable explaining this project publicly if the cancellation is scrutinised?

Those gates should be passed in order. There is little value in doing a deep quality review on a unit that is outside the eligible scope. There is also little value in buying a technically eligible unit if the supporting evidence is too weak for audit, verifier review or public communications. The strongest procurement files connect ICAO eligibility, registry evidence and quality review in one place.

For more depth, use the CORSIA eligible programmes guide for programme-level checks, the CORSIA credit prices guide for procurement context, the Article 6 guide for the wider rulebook and the corresponding adjustments guide for host-country accounting evidence.

Buyer checklist for airlines

Start with the ICAO list. Check the latest CORSIA Eligible Emissions Units document, not an old broker deck.

Match the compliance period. A unit eligible for one period may not automatically be eligible for another.

Check scope limitations. Confirm vintage, activity type, methodology, registry and country restrictions.

Ask for registry evidence. The project ID, serial numbers and cancellation record should be traceable.

Check Article 6 documentation. Where required, ask how host country authorisation and corresponding adjustments are handled.

Separate compliance from reputation. A unit can be compliance-eligible but still bring reputational risk if the project quality is weak.

Tool via The Carbon Workbench

Common mistakes

The first mistake is treating "CORSIA eligible" as a generic marketing label. It is a specific compliance status tied to ICAO documents, dates and eligibility limitations.

The second mistake is ignoring vintage and scope. A credit from an approved programme can still fall outside the approved CORSIA scope.

The third mistake is confusing purchase with cancellation. Holding a credit is not the same as cancelling it for compliance.

The fourth mistake is treating eligibility as quality due diligence. Airlines still need project-level risk review, particularly for credits that may attract public scrutiny.

Eligibility is only the first screen

CORSIA eligibility should not be treated as a complete credit-quality verdict. It tells an airline whether a unit can potentially be used for the scheme, subject to the relevant phase, vintage, programme rules and accounting requirements. It does not automatically answer every question about project quality, permanence, baseline risk, host-country authorisation or public claims outside the aviation context.

That distinction matters because an airline compliance buyer and a voluntary corporate buyer may be trying to solve different problems. An airline needs eligible emissions units for a defined compliance obligation. A company making a climate claim needs to consider the VCMI Claims Code, credit quality, retirement wording and greenwashing risk. The safest approach is to treat CORSIA eligibility as one part of a wider evidence file, then check the project, programme, vintage and claim separately before relying on the credit.

Useful source links

• ICAO CORSIA eligible emissions units
• ICAO CORSIA FAQ
• ICAO CORSIA implementation elements

Key takeaway

CORSIA eligibility is specific. Airlines need units from programmes approved by ICAO, within the right compliance period and eligibility scope, with proper cancellation evidence. But eligibility is not the same as full quality assurance. The best buyers check both.