Register your plant in the EU CBAM Registry (O3CI): step by step
Producers outside the EU can upload their plant and emissions data once and share it with their EU buyers. The three registration steps, the documents, and the company number to use for your country.
Checked against the EU rules on 6 October 2026.
The EU CBAM Registry has a portal for operators of installations outside the EU, called O3CI. You enter your installation and its emissions once, add your verifier's report, and share them with your EU buyers. Their CBAM declarants then take the figures straight into their declaration, instead of you sending a spreadsheet to each buyer.
Step 1: create an EU Login account
- Go to webgate.ec.europa.eu/cas and register with an email address. A company address is strongly recommended.
- Set up two-factor authentication: the EU Login app, a QR code or a FIDO2 key.
- Each person who will use the portal registers individually.
Step 2: submit the access request
- Go to cbam.ec.europa.eu/o3cinstallation and sign in with EU Login.
- Fill in the onboarding form: company details and registration number, company email and website, and your role, Admin Operator or Simple Operator.
- Upload one PDF with: the company registration certificate (its number must match the one in the form), proof of representation such as a power of attorney, and the ID of the authorised representative. The Commission strongly recommends English, for example a courtesy translation next to the originals.
Which company number to use
| Country | Identifier the Commission recommends |
|---|---|
| China | Unified Social Credit (USC) number |
| India | Corporate Identification Number (CIN) or LLP Identification Number (LLPIN) |
| South Korea | Business registration number |
| Türkiye | Vergi Kimlik Numarası (tax number) |
| United Kingdom | Company Registration Number (CRN) |
| Other countries | Business or trade register number, tax identification number, or Legal Entity Identifier (LEI) |
The Commission's examples start with the two-letter country code, for example IN for India.
Step 3: wait for approval
Review and submit the request, then watch the email address of your EU Login account. Approval may take several weeks, so apply well before your buyers need your figures.
After approval
- Add your installation and its production processes.
- Upload your emissions data and the report of your accredited verifier.
- Share the data with your buyers. Ask each EU buyer for their EORI number, which identifies them in the registry.
Checklist before you start
- A company email address for each person who will use the portal.
- A phone or security key for two-factor login.
- Your company registration certificate, with the number you will type in the form.
- A power of attorney or other proof that the person applying may act for the company.
- ID of that person.
- English translations of these documents.
- The EORI numbers of your EU buyers.
Help
CBAM helpdesk: support@itsmtaxud.europa.eu, Monday to Friday 07:00 to 21:00 CET. Include screenshots of the error, the exact URL and the time. Prepare your figures first with the emissions calculator and the verification checklist.
Based on the Commission's CBAM Registration Guide for non-EU operators (February 2026, © European Union, CC BY 4.0), translated and adapted. Check the CBAM Registry page for the current manuals.
General information for planning, not legal, tax or customs advice. See the disclaimer.