CBAM 2026: What the EU Carbon Border Tax Means for Mexican Exporters

CBAM, the EU's Carbon Border Adjustment Mechanism, entered its definitive regime on 1 January 2026. The transitional phase (2023-2025), which only required emissions reporting, is over: importing certain goods into the EU now carries a cost for the carbon embedded in them, and that changes the rules for Mexican exporters selling into Europe.

How CBAM works

The mechanism makes goods entering the EU carry a cost equivalent to the carbon emitted in their production, linked to the price of allowances under the EU Emissions Trading System (ETS). If a carbon price has demonstrably already been paid in the country of origin, that amount is deducted.

One point is worth getting straight: the formal obligation sits with the EU importer, who must be authorised as a CBAM declarant, file the annual declaration and surrender the corresponding certificates. The Mexican exporter does not report to the EU, but does hold the emissions data the European customer needs. Without it, the customer falls back on default values, which are usually less favourable. There is more detail on the mechanism in our CBAM 2026 guide and in the glossary entry on the carbon border adjustment mechanism.

Sectors covered today

• Cement
• Iron and steel
• Aluminium
• Fertilisers
• Electricity
• Hydrogen

Since 2026 there is a de minimis threshold of 50 tonnes of net mass per year per importer, aggregated across all covered goods. Below that figure there is no obligation; once it is crossed, the obligation covers the whole year, with no retroactive exemption. The threshold applies to cement, iron and steel, aluminium and fertilisers: electricity and hydrogen fall outside it and are always covered. The annual declaration is due by 30 September of the following year.

The list started narrow, but its reach extends to entire manufacturing chains that depend on these inputs, including a large share of Mexico's export industry.

Timeline and certificate price

According to the European Commission's questions and answers, updated in May 2026, the first CBAM declaration, covering 2026 imports, is due by 30 September 2027, and certificates are surrendered on the same date. Certificate sales start on 1 February 2027. For 2026 imports the price is calculated as a quarterly average of ETS auctions, published on 7 April, 6 July and 5 October 2026 and 4 January 2027; from 2027 it becomes a weekly average.

When the importer has no verified actual data, it applies default values that include a mark-up so that emissions are not underestimated: 10% in 2026, 20% in 2027 and 30% from 2028, with a reduced 1% mark-up for fertilisers. That mark-up is the clearest commercial argument for a Mexican exporter to measure and verify its embedded carbon.

Why this matters specifically for Mexico

Mexico exports a high volume of manufactured goods and its industrial base includes energy-intensive sectors, precisely the ones CBAM covers. As the mechanism beds in and, where applicable, extends to more sectors, more Mexican companies will need to document the carbon embedded in what they sell to Europe.

What you need to stay competitive

• Product-level measurement, not just plant-level: CBAM asks for the embedded carbon of each exported good, not just a company-wide total.
• Supplier traceability: most of an exported product's footprint originates in the supply chain, not the final assembly plant.
• Evidence of a carbon price already paid: if your company bears a carbon price in Mexico, you need verifiable data to prove it so that it can be deducted in the EU.
• Registration as a third-country operator: the Commission allows operators of installations outside the EU to access the CBAM Registry, have their embedded emissions verified by an accredited CBAM verifier and communicate them to their importing customers through the official template. It is the route for your actual data to replace the default value in your customer's declaration.

A caveat on carbon pricing in Mexico

This is where the picture is often misread. Mexico's Emissions Trading System (SCE) is still in its pilot phase, with free allocation of allowances and no auctions, meaning participants do not actually pay a price. On its own, it therefore does not support a CBAM deduction today.

The instruments that do involve a payment are the federal carbon tax, applied through the IEPS excise on fossil fuels, and the state-level carbon taxes that, according to the International Carbon Action Partnership's inventory, are in force in Colima, Durango, Guanajuato, Mexico City, Morelos, Querétaro, San Luis Potosí, the State of Mexico, Tamaulipas, Yucatán and Zacatecas. If your company bears them, it is worth documenting the amount attributable to each exported product and working it through with your European customer, because the deduction requires traceability rather than a general statement. The Commission has announced an implementing act in 2026 that will define what evidence is required, certification by independent persons and the conversion rules, and plans to publish default carbon prices by country. The General Law on Climate Change is the framework these instruments hang from.

How to prepare

The challenge is not just compliance, it is compliance without losing margin. Measuring the product and supply chain footprint with real data instead of generic estimates is what lets you document the embedded carbon CBAM requires and protect your access to the European market. You can do it with Manglai's product carbon footprint module.