Buying Carbon Credits Step by Step: Enquiry to Certificate

The four stages of a purchase on our desk, from holding a lot to receiving a retirement certificate, and what you should have ready at each one.

Most first-time buyers we speak to expect buying carbon credits to work like an online checkout. It does not. A credit is a registry entry tied to a specific project, vintage and serial range, so the purchase is really a short sequence of checks that ends with units moving between registry accounts. This page walks through that sequence as we run it, and lists what you can prepare in advance so nothing stalls.

Before you contact us

Two things save more time than anything else.

Know your purpose. A sustainability team offsetting the travel footprint of a Pune IT firm has different needs from an airline meeting a CORSIA obligation. The first may care most about project type and co-benefits; the second must meet strict eligibility rules. Write down why you are buying, because every later decision follows from it.

Know your limits. Decide which standards or programmes you will accept, the oldest vintage you are comfortable with, any project types you want to exclude, and a rough volume in tonnes of CO₂ equivalent (tCO₂e). If you prefer to put this in a structured form, you can post a requirement on our intake platform, which asks for volume, accepted programmes and vintages, CORSIA or Article 6 conditions, and exclusions.

If you are browsing first, the marketplace lets you filter by category, registry and delivery type. On any project page you can enter a quantity to see an estimated total, then choose "Request to buy", which opens our contact form already filled in, or message us on WhatsApp.

Step 1: Choose and hold

You tell us which lot you want and how many tonnes. We hold it and confirm in writing the availability, vintage and registry details.

That written confirmation matters because the price on a listing is indicative. It becomes firm only once we have confirmed availability, vintage, registry details and eligibility for your purpose. Until then, treat any figure you see as a guide for budgeting, not a quote.

What you prepare: the lot name or registry ID, the quantity, your purpose, and the name of the organisation that will own or benefit from the credits.

Step 2: Due diligence

Once a lot is held, we share the project documents with you before any contract is signed. These usually include the Project Design Document (the developer's plan for how reductions or removals will be achieved and measured), the validation report from an independent auditor, the latest verification report, and the registry issuance record. Our page on project documents explains what to look for in each.

The aim of this stage is simple: check the units against your own requirement. Does the methodology suit your policy? Is the vintage inside your window? If you need CORSIA-eligible units, does the documentation show the right programme and host-country authorisation? Can you match the serial numbers to the public registry?

What you prepare: whoever reviews the documents on your side, whether that is a sustainability lead, an external consultant or your auditor. Large buyers often have an internal checklist; if you do not, list your three or four non-negotiables and test each document against them.

Step 3: Transfer or retire

At this point you choose how you take the credits. There are two routes:

Transfer. The units move into your own account on the relevant registry. You then decide when to retire them, or, for CORSIA, cancel them in line with your national process.
Retirement on your behalf. We retire the units for you, in the name of the beneficiary you choose. This suits buyers who do not want to open and maintain a registry account.

Neither route is better in every case. Our guide to registry accounts for buyers sets out the trade-offs.

What you prepare: for a transfer, your registry account details. For retirement on your behalf, the exact beneficiary name as you want it to appear and, if relevant, a short retirement purpose such as "2025 business travel emissions". Spell the legal name carefully; registries do not easily correct it afterwards.

Step 4: Proof

You receive the retirement certificate and the serial numbers, packaged as a file your auditors can check. The registry, not us, is the official record of issuance and retirement, so the serial numbers let anyone confirm the retirement on the registry's public database.

What you prepare: a place to keep this evidence alongside your emissions inventory. Auditors, assurance providers and, for airlines, the national authority may ask for it later. Our article on retirement certificates explains how to read the certificate and verify it yourself.

A note on payment and contracts

No payment is taken on this website. Commercial terms are agreed directly with the desk after due diligence, and documents are always shared before any contract. If someone claiming to act for us asks for payment through a link or before you have seen documents, stop and call us on the number on our contact page.

Where purchases usually slow down

From our experience, delays rarely come from the registry itself. They come from:

an unclear purpose, so the buyer's team changes its mind about vintage or project type halfway through;
approval chains, where a legal or finance team sees the documents for the first time late in the process;
beneficiary details that do not match the buyer's legal entity name;
for CORSIA buyers, uncertainty over whether a lot carries the authorisation the operator needs.

Settling these early, ideally before Step 1, is the single best way to keep a purchase short.

When you have a purpose and a rough volume in mind, browse the marketplace or send us your requirement and we will suggest lots that fit.