Blue carbon credits are among the most requested and least available credits in the voluntary market. Buyers like them for good reasons: coastal ecosystems store unusual amounts of carbon, protect coastlines and support fisheries. The supply of credited projects is small, though, and quality varies.
Blue carbon credits come from projects that protect or restore coastal ecosystems, mainly mangroves, seagrass meadows and tidal salt marshes. Each credit represents one tonne of CO2 equivalent (tCO2e) avoided or removed and certified by a standard such as Verra. This article explains why these ecosystems matter for carbon, how blue carbon credits are created, what they cost and which risks a buyer should check.
What blue carbon is
“Blue carbon” is the carbon captured and stored by coastal and marine ecosystems. Three ecosystems account for most of what is credited:
Mangroves, salt-tolerant forests along tropical and subtropical coasts.
Seagrass meadows, underwater flowering plants in shallow coastal waters.
Tidal salt marshes, grassy wetlands flooded by the tide, mostly in temperate zones.
What sets them apart is where the carbon sits. Their soils are waterlogged and low in oxygen, so dead plant material decomposes very slowly and builds up over centuries. A study of 25 mangrove forests in the Indo-Pacific found they store up to four times as much carbon as other tropical forests, most of it in the soil (Donato et al., Nature Geoscience, 2011).
That works in both directions. When mangroves are cleared for shrimp farms, rice or charcoal, the stored soil carbon is released. Protecting what exists avoids large emissions; restoring what was lost removes CO2 again over time.
How blue carbon credits are created
Blue carbon projects follow the same chain as any carbon credit: methodology, validation, monitoring, verification and issuance (how carbon credits work). They come in two forms:
Restoration, such as replanting mangroves or rewetting tidal marshes. These generate removal credits as the vegetation and soil take up carbon.
Conservation, protecting existing mangroves from clearing. These generate avoidance credits under REDD+-type methodologies.
Many large projects combine both. Under Verra, the main methodology for tidal wetland and seagrass restoration is VM0033. Its version 2.1 has applied since 2023, and Verra ran a public consultation on a major revision, version 3.0, from September to October 2026 (Verra VM0033). Projects often add the Climate, Community and Biodiversity (CCB) Standards to certify their social and ecological benefits.
Seagrass and salt marsh credits are still rare, mostly because measuring their carbon is harder. In practice, most blue carbon credits a company can buy today come from mangroves.
An example: Delta Blue Carbon in Pakistan
The largest credited mangrove project is Delta Blue Carbon in the Indus Delta, Sindh, Pakistan (Verra VCS 2250, with CCB certification). It aims to protect about 102,000 hectares of existing mangroves and restore around 225,000 hectares of degraded land with local communities, combining assisted natural regeneration and replanting. The project targets 142 million tonnes of CO2 equivalent over 60 years and reports around 21,000 jobs created, about half the local population (project page).
Its credits have public buyers: Microsoft, Trafigura, Respira and Carbon Growth Partners bought the first tranche in 2022, and Commerzbank has retired credits from the project every year since 2024, most recently in May 2026.
Barista Company, an events coffee company, chose mangrove reforestation for its annual offsetting programme with Regreener, partly for the biodiversity and community benefits alongside carbon.
Credits or contributions: two ways to support mangroves
Not every mangrove project issues carbon credits. Some restoration programmes, such as the mangrove restoration in Maranhão, Brazil that Regreener supports (project page), are funded per tree or per hectare and monitored with satellite data, without certified credits.
Both are valid, for different purposes:
Certified blue carbon credits fit when you want verified tonnes, retired in your name, for a contribution claim or a removal target.
Restoration contributions fit when the goal is ecosystem and community impact, and you communicate it as such, not as tonnes compensated.
Mixing the two up is a common communication error. A per-tree contribution should never be reported as offset emissions.
What blue carbon credits cost
Blue carbon credits trade at a premium over most nature-based credits, because supply is small and demand from buyers who value co-benefits is strong. S&P Global Platts reported its blue carbon price assessment at a record high in August 2025, with a reported trade of USD 30.50 per tonne for credits from Delta Blue Carbon (S&P Global). For comparison, high-rated reforestation credits averaged USD 28.55 in the first half of 2026 (carbon credit prices in 2026).
Prices for a specific project depend on vintage, volume, whether credits are removals or avoidance, and the project’s rating.
Risks to check before buying blue carbon credits
Blue carbon has strong co-benefits and real risks. Ask about each of these:
Survival and growth. Mangrove planting can fail when species, site elevation or hydrology are wrong. Ask for monitored survival rates and how they feed into issuance.
Permanence. Cyclones, erosion and sea-level rise can damage coastal ecosystems. Check the project’s risk rating and its buffer pool contribution.
Baseline for conservation. For avoidance credits, ask how the deforestation threat was evidenced. The same over-crediting risk applies as for other forest protection (additionality).
Soil carbon measurement. Most of the carbon is in the sediment. Ask whether soil carbon is measured on site or estimated with default values.
Community rights and benefit sharing. Coastal land is often used by fishing communities without formal title. Check consent processes, benefit-sharing agreements and the CCB certification.
Tip from Bernard de Wit, Founder of Regreener: “With mangroves, ask to see the planting records next to the satellite imagery. A project that knows its survival rate per site and adjusts issuance to it is managing the risk. One that reports trees planted but not trees alive is selling a planting number, which is a different thing from a carbon number.”
Where blue carbon fits in a portfolio
Blue carbon credits are nature-based, mostly short-lived removals or avoidance in SBTi’s terms, with exceptional co-benefits: coastal protection, fisheries and biodiversity. They suit companies that want a project they can explain and visit in their story, and that value impact beyond carbon. They do not replace durable removals for long-term neutralisation (carbon dioxide removal explained).
“Blue carbon is where carbon finance and adaptation meet. In the Indus Delta the mangroves are also a flood defence for coastal villages. That makes them one of the few credits where we can show a client the climate benefit and the local benefit in the same place.”
Bernard de Wit, Founder of Regreener
Support a blue carbon project
See the mangrove projects in our portfolio, from credited conservation and restoration in the Indus Delta to community restoration in Brazil.
