Who Owns Blue Carbon? Tenure, Rights and the Sea

Before a blue carbon project measures a single core of sediment, it must answer an older question than any carbon accounting: whose sea is this? Coastal waters are layered with rights — national jurisdiction, state or provincial authority, customary and Indigenous tenure, fishing licenses, leases, protected-area designations. A carbon credit is a claim about that place, and claims only stand if the rights underneath them do. Tenure is not a hurdle to clear before the real work; it is the real work.

The jurisdictional stack: who governs what strip of sea

Ocean rights arrive in bands, each with its own law:

• Territorial sea (generally to 12 nautical miles): full coastal-state sovereignty, usually delegated down to subnational governments for day-to-day coastal management.
• Contiguous zone and EEZ (to 200 nautical miles): sovereign rights over resources, including the seabed and water column — under the UN Convention on the Law of the Sea, states control activities like artificial-reef construction and aquaculture here.
• High seas: beyond national jurisdiction, where the emerging BBNJ framework and London Protocol rules apply.

Within the territorial sea, jurisdictions split further. In many federations, subnational states or provinces own the seabed to three nautical miles while the national government controls beyond. Local councils may hold foreshore powers. Ports may have their own statutory authority. A single restoration site can sit across three legal regimes before breakfast.

Carbon rights are not the same as land or sea rights

Here is the trap that catches most newcomers: owning the seabed does not automatically mean owning the carbon in it. Carbon rights — the legal entitlement to claim, sell and retire sequestration benefits — are a distinct legal layer, and countries handle them differently:

• Some jurisdictions treat carbon sequestration as attached to the underlying tenure (the landowner or seabed rights-holder owns the carbon).
• Some have created standalone, registrable carbon rights separate from tenure.
• Some have no carbon-rights legislation at all, leaving ownership to contract — which works only if the counterparties actually hold the underlying rights.
• A growing number of governments assert state ownership of carbon in public waters or demand revenue-sharing from credits generated on public estate.

The developer's due-diligence question is therefore never just "who leases this site?" but "which legal persons can grant the carbon rights, and are any of them the same?"

Customary tenure and Indigenous sea country

Across much of the world's coastline — Australia, the Pacific Islands, coastal Canada, Aotearoa New Zealand, Southeast Asia — the deepest rights in coastal waters are customary: Indigenous systems of sea tenure that long predate, and often legally coexist with, state law.

These systems come in several legal forms: statutory native title and sea-country determinations, treaty rights, customary marine tenure recognised in national law (including the widespread community-managed fishing areas across the Pacific), and constitutional or statutory rights of consultation and consent. Two practical consequences follow:

1. Consent is often a legal requirement, not a courtesy. Where native title or customary tenure applies, projects may lawfully require Indigenous consent or agreement-making before any approval sticks.
2. Even where not legally required, free, prior and informed consent is the ethical floor — the standard set out in the UN Declaration on the Rights of Indigenous Peoples and now embedded in most credible carbon standards' safeguard requirements. We detail what FPIC looks like in practice in Blue Carbon on Sea Country.

Getting this right is also simply better science and better business. Indigenous knowledge of seasonal cycles, species and site history routinely improves baselines, and ranger programs are among the most effective long-term monitoring workforces a coastal project can have — exactly the model behind Tidewright's fictional Reef Partners program and our community solutions.

Competing rights and overlapping claims

Even after you've mapped jurisdiction and Indigenous tenure, the water column remains crowded:

• Fishing licenses and quota holders whose effort your restoration might displace or enhance.
• Aquaculture leases with exclusive-possession terms that may exclude carbon project activity.
• Marine protected areas, where management plans may prohibit, permit or condition restoration — and where the MPA authority itself may claim resulting benefits.
• Ports, defence zones, cables and shipping lanes that hard-constrain where projects can physically operate.
• National carbon accounting: under Paris Agreement frameworks, removals inside a country's territory may already count toward its national inventory — raising double-counting questions over who, project or state, gets to claim the tonne.

Each layer needs a documented answer before credits are designed, not after.

How developers resolve tenure in practice

The workable playbook, distilled from wetland and mangrove projects worldwide:

1. Map every rights layer early — statutory, customary, licensed, de facto. Coastal atlases and government tenure registries help, but nothing substitutes for asking the community.
2. Secure agreements, not assumptions — written benefit-sharing and consent agreements with every rights-holder whose interests the project touches, with legal review in the local system.
3. Define carbon rights explicitly in contract — who owns the credit, who can sell it, what happens on transfer of tenure or project exit.
4. Register everything possible — on the carbon registry and, where available, national tenure registers. Registries are the claim's public face; contracts are its legal spine.
5. Plan for succession — fishing licenses lapse, governments change, customary authority endures. Design agreements that survive all three.

The equity question underneath the technical one

Tenure is technical; it is also moral. Blue carbon finance will flow preferentially to places where rights are documented — which historically means places where Indigenous and customary rights were extinguished or ignored, and against communities whose tenure is real but unregistered. If the market only rewards formal title, it will channel restoration money toward the already-privileged coastlines and away from many of the ecosystems and stewards who most need it.

Serious standards bodies are responding: requiring FPIC, benefit-sharing plans, and grievance mechanisms as conditions of certification. The deeper fix is policy — legal recognition of customary marine tenure and explicit provisions for community carbon rights — which is why tenure reform rides alongside methodology development on the blue carbon policy agenda.

What this means if you're buying credits

For corporate buyers, tenure diligence is reputational diligence. Ask every project: Who holds the underlying rights? Is there written evidence of consent — and from whom, exactly? How are benefits shared? Is any claim on this carbon also made in a national inventory, and how is that reconciled? Our buyer's guide puts these questions in a checklist; credentials that include social-safeguard certification should be treated as increasingly non-negotiable, not a premium extra.

Key takeaways

• Carbon rights are a separate legal layer from seabed and water tenure — check who can grant them, not merely who leases the site.
• Jurisdiction bands (territorial sea, EEZ, high seas) and subnational splits mean one project can touch multiple legal regimes.
• Customary and Indigenous tenure is foundational on a huge share of coastlines; consent is frequently a legal requirement and always an ethical one.
• Fishing rights, MPA rules, national inventories and leases layer on top; every overlap needs a documented answer before credits are designed.
• Written benefit-sharing, explicit carbon-ownership contracts, and registry records are the project's legal spine.

FAQ

Who owns the carbon in the ocean in my country?

It depends on your country's law: some attach carbon rights to underlying tenure, some register them separately, some reserve them for the state, and some have no rules yet. A local legal opinion on carbon rights is a mandatory early project cost.

Do I need community consent even if the law doesn't strictly require it?

Yes. Credible carbon standards increasingly require free, prior and informed consent as a certification condition, and a project opposed by its community will ultimately fail ecologically, legally or both.

Can a government claim the same carbon as a private project?

It can — removals within a country's territory may enter its national inventory under the Paris Agreement, creating double-claiming risk. Reconciliation through national registries and Article 6 corresponding adjustments is the emerging answer; see double counting explained.

What happens to carbon credits if a lease or title changes hands?

Whatever the contract says — which is why credits must be legally separable, documented, and designed for succession. Projects that skip this find their credits unsellable on the secondary market.

Is there any coast without tenure issues?

No. Even apparently empty foreshores carry jurisdictional, environmental and often customary layers. The difference between good and bad projects is whether the mapping happens first.