Deep Sea Mining Companies and Machine Makers Compared

No company holds a licence for commercial seabed mining in international waters as of 16 October 2026. The closest is The Metals Company (TMC, Nasdaq: TMC), whose consolidated US application NOAA found fully compliant with the information requirements of the Deep Seabed Hard Mineral Resources Act, as announced on 19 August 2026 (NOAA, 19 August 2026). NOAA has not yet certified it. TMC expects a permit before the end of the first quarter of 2027 (TMC Form 8-K, 1 May 2026), which is the company’s forecast. The machines come from a short list of offshore engineering firms, mainly Allseas and the GSR unit of DEME. The International Seabed Authority (ISA) lists 22 exploration contractors, but it has not yet adopted the rules that would allow mining to start.

This page answers four questions in order: who the companies are, who builds the underwater mining machines, what the rules and timetable look like, and what the field tests found about the environment. It also covers the rare earth angle, because rare earths and nodule metals are often mixed up. Every figure carries its source and date.

How we chose the companies in this guide

We included an organisation only if public records show at least one of three things: it holds an ISA exploration contract, it has filed a seabed mining application with a national regulator, or it built a collector or lift system that has worked on the seabed. This is a selection, not a complete directory. The ISA alone lists 22 contractors, and we do not claim to cover them all.

We left out price targets, share prices and any buy or sell view. Stock details are limited to the exchange and ticker named in company filings. This page is for information only and is not investment advice.

Seabed mining companies compared

The table sorts organisations by what they actually do: hold licences, build machines or test technology. Status is as reported in the sources named in the last column.

Two corrections to older lists, including the previous version of this page. Nautilus Minerals is no longer an active developer, and DeepGreen Metals is not a separate company from TMC: DeepGreen is the name TMC used before its 2021 listing on Nasdaq (reference summary of TMC’s history). For more on American-listed names, see our overview of US-linked seabed firms.

Who makes underwater mining machines?

There is no catalogue of seabed mining machines you can buy. Each collector is built for a specific project by an offshore engineering contractor, then tested on the seabed with scientists watching. Two builders have tested full-scale pre-prototype collectors on the seabed, both for nodules.

Allseas and the Hidden Gem system

Allseas designed the pilot collector vehicle and the riser that TMC’s subsidiary NORI used in the CCZ in late 2022. TMC reported that the vehicle drove more than 80 km, sustained 86.4 tonnes per hour and moved over 3,000 tonnes of nodules up a 4.3 km riser to the ship Hidden Gem, with another 1,500 tonnes left on the seafloor on purpose (Offshore Engineer, 14 November 2022). These are company-reported figures. On 11 May 2026 TMC announced a contract under which Allseas will complete and operate the first commercial nodule collection system: two collector vehicles, a riser, the Hidden Gem and a transfer vessel, with a nameplate capacity of 3 million wet tonnes a year. Allseas will fund a significant part of the development cost, recoverable from production revenue, and TMC calls Allseas its largest shareholder (International Mining, 11 May 2026, reprinting TMC’s announcement).

GSR and the Patania II collector

Patania II is a tracked pre-prototype with four vacuum-style collector heads. A waterjet above the nodules creates negative pressure that lifts them off the seabed, and the nodules are separated from the sediment, which is returned to the seafloor. It is powered and controlled through a cable of about 5 tonnes from the support ship (DEME GSR). On 25 April 2021 a lifting point separated and the vehicle came off its cable. It was recovered on 29 April (Baird Maritime, 2 May 2021). DEME said GSR would apply for a mining contract only if the science shows the seabed can be a responsible source of metals.

Impossible Metals and the Eureka robot

Impossible Metals describes Eureka as an autonomous underwater vehicle that hovers above the seabed and picks nodules selectively, avoiding those with visible life (company release, 16 April 2025). That is the company’s description, not an independent test result. Its route is a lease on the US outer continental shelf, not a high-seas licence. The Congressional Research Service notes that BOEM had issued no critical mineral leases as of 28 August 2026 (CRS, 28 August 2026). The same report lists a November 2025 request from Odyssey Marine Exploration for a lease sale for heavy mineral sands and phosphorites off Virginia.

Other equipment on the job

Beyond the collector, a project needs a riser or lift system, a production ship, remotely operated vehicles for inspection and autonomous vehicles for monitoring. Japan’s rare earth mud test uses a scientific drill ship rather than a nodule collector. For general reading on mining equipment and sensors, see our notes on mineral technology and mining innovations.

How seabed nodule collectors work

Polymetallic nodules are potato-sized lumps that lie on the abyssal plain at depths of about 3,000 to 6,000 metres (GEOMAR, March 2025). They were first brought up by the HMS Challenger expedition on 7 March 1873 (ISA). A nodule system has four jobs: pick the nodules up, separate them from mud, lift them to a ship and move them ashore for processing.

Infographic

A nodule system in 4 steps

1. 1CollectA tracked collector lifts nodules off the seabed with the top layer of sediment.
2. 2SeparateNodules are split from the sediment, which is returned to the seafloor (GSR design).
3. 3LiftA riser pipe brings the nodules up to the production ship, as in the 2022 Allseas pilot.
4. 4Ship and processNodules go ashore to be processed into nickel, copper, cobalt and manganese products.

Because nodules sit on the seabed surface rather than in a rock body, these collectors work the surface layer instead of cutting rock. In the 2021 Patania II test, nodules were removed together with at least the top 5 cm of the seafloor (see the environmental section below), and the sediment is where much of the life and most of the disturbance sits.

How much metal is on the seabed

The ISA’s geological model study estimates that the CCZ study area holds about 21,100 million tonnes of nodules, containing roughly 5,950 million tonnes of manganese, 270 million tonnes of nickel, 234 million tonnes of copper and 46 million tonnes of cobalt. These are inferred resource estimates from sampling, not reserves, and they date from 2010 (ISA Technical Study No. 6, 2010). The study’s mean grades on a dry basis are 29.0% manganese, 1.34% nickel, 1.14% copper and 0.23% cobalt.

Chart

CCZ nodule metal estimate as a share of USGS world land reserves

Per cent: ISA inferred resource estimate divided by USGS 2025 world reserves (nickel reserves are a floor, over 140 Mt)

To judge the scale, compare those estimates with what the US Geological Survey counts as economic reserves on land. USGS puts world reserves at more than 140 million tonnes of nickel, 12 million tonnes of cobalt, 980 million tonnes of copper and 1.8 billion tonnes of manganese (USGS, Mineral Commodity Summaries 2026). Resources and reserves are different measures, so the comparison shows scale rather than value.

Rare earths are not on this list. The metals in nodules are manganese, nickel, copper and cobalt, which is why the nodule projects described here are battery and steel projects, not rare earth projects.

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Why cobalt and nickel supply concentration drives interest

Supply of the two battery metals is concentrated on land. USGS reports that the Democratic Republic of the Congo mined 230,000 of the world’s 310,000 tonnes of cobalt in 2025 (estimate), and Indonesia mined 2.6 million of 3.9 million tonnes of nickel (USGS nickel, 2026). Shares are calculated from the USGS tables. Nodule developers point to this concentration when they describe the case for a second source, while Norway’s environment agency and others point to gaps in knowledge about deep-sea ecosystems (Marine Technology News, December 2025). The size of the resource is not the argument in dispute; supply risk and ecology are.

Chart

Share of world cobalt mine output by country

Per cent of world cobalt mine production, selected countries (2024; 2025 estimate)

ISA contracts and the US permit route

Outside national waters, the ISA grants 15-year exploration contracts. Its list shows 22 contractors and, among live contracts, 19 for polymetallic nodules, 7 for polymetallic sulphides and 5 for cobalt-rich crusts. One contract, held by the Brazilian company CPRM, was renounced on 28 December 2021 (ISA exploration contracts). Seventeen of the nodule contracts are in the CCZ.

Chart

Live ISA exploration contracts by mineral type

Number of contracts (22 contractors)

The United States is not a member of the ISA. It uses the Deep Seabed Hard Mineral Resources Act of 1980, under which NOAA can issue exploration licences and commercial recovery permits to US companies. Executive Order 14285, issued in April 2025, told agencies to speed up seabed minerals work. On 21 January 2026 NOAA published a final rule (91 FR 2642) that lets applicants file for an exploration licence and a commercial permit together (Gradient, 24 April 2026). NOAA says TMC USA submitted the first consolidated application on 6 February 2026; TMC and Gradient give 22 January. NOAA found it in substantial compliance on 9 March 2026.

The applicants named in the NOAA Federal Register notices we opened, as of 13 October 2026, are: TMC USA (exploration applications A and B, notice of 23 December 2025, plus the consolidated application, notice of 19 August 2026), American Metal Resources, LLC and SeaX (notice of 23 March 2026, hearings 21 and 22 April 2026), and American Deep Sea Minerals, Inc. (notice published 2 June 2026, hearing 1 July 2026). See the March 2026 notice and the June 2026 notice. This is the list in the notices we read, not NOAA’s complete register. Impossible Metals and Odyssey use the separate BOEM route for US federal waters.

Where the rules and timetable stand

The ISA still has no mining code. The Council ended its March 2026 session on 19 March without agreement. The Council ended its July meeting on 24 July without adopting the code, and the Assembly closed Part II of the 31st session on 31 July. Environmental safeguards, liability, inspection and benefit-sharing remain open, and experts quoted by Benchmark expect at least three to four more years of talks (Benchmark Mineral Intelligence, 14 August 2026). The ISA says negotiations resume in March 2027. The Council meets from 8 to 19 March and from 12 to 23 July 2027, and the 32nd Assembly runs from 26 to 30 July 2027 (ISA, 13 October 2026).

The expected permit date is the company’s own forecast, not a NOAA commitment. NOAA’s decision follows an environmental impact statement and public comment.

Countries that have paused or opposed it

Norway ruled out seabed mining licences in its waters until at least the end of 2029 and withdrew public funding for government-led mineral mapping (UN Regional Information Centre, December 2025). By December 2025, 40 countries had taken a clear stance against the industry, the European Parliament had called for a moratorium and the European Investment Bank had excluded seabed minerals from financing. In November 2025 the Cook Islands announced five-year extensions for deep sea applications, which delays mining there until at least 2032 (Marine Technology News, 4 December 2025).

Listed seabed mining names: facts, not tips

This section names the listed companies that have seabed mining projects. TMC trades on Nasdaq under TMC. Odyssey Marine Exploration trades on Nasdaq under OMEX and announced a merger with American Ocean Minerals on 8 April 2026. The 6 October 2026 SEC filing shows the merger pending, with the combined company expected to trade as AOMC (Odyssey Form S-4/A, 6 October 2026). Global Mining Review also reports that TMC announced the direct listing of The Metals Royalty Company, which holds a 2% royalty on TMC’s NORI nodule project. GSR is the deep-sea exploratory division of DEME Group NV, so DEME’s results are not a seabed-only measure. For a longer background list, see our earlier piece on publicly traded names and the notes on polymetallic nodule companies.

None of these companies had started commercial seabed production as of 16 October 2026. Permits, test results and financing are still open. Read each company’s annual report and risk factors on SEC EDGAR before drawing any conclusion. This is not investment advice.

Environmental impacts: what field tests measured

Two sets of evidence matter most. The first is the DISCOL experiment, in which a plough-harrow was dragged across the Peru Basin seabed in 1989 to mimic mining. When scientists returned 26 years later, suspension feeders such as sponges and anthozoans (corals and anemones) were still much less common in the tracks, and diversity was lower in the disturbed area than in the reference area (Simon-Lledo et al., Scientific Reports, 2019).

The second is the 2021 monitoring of GSR’s Patania II in the CCZ. Over 41 hours the vehicle travelled about 20 km and covered 34,000 square metres. Near the site, sediment concentrations were up to 10,000 times natural levels and returned to normal after 14 hours. Most particles stayed within 5 metres of the seafloor, but small changes were detectable 4.5 km away. A redeposited layer about 3 cm thick covered the nodule habitat within about 100 m, and the collector removed at least the top 5 cm of the seafloor where it worked (Marine Technology News on the Nature Communications study, March 2025). The authors describe the data as the first detailed look at the far-field footprint.

What the tests do not show is the effect of a full-scale operation running for years, or how the midwater discharge from a riser behaves over time. For the permit steps that cover these gaps, see our guide to environmental impact assessment in mining.

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Deep sea mining for rare earth minerals

Rare earth elements such as neodymium and dysprosium go into the permanent magnets used in electric vehicle motors and wind turbines. For readers new to the group, our explainer on what a rare earth metal is gives the basics. Japan’s government test is the main seabed rare earth work in the sources we reviewed, and it is about mud, not nodules.

The drill ship Chikyu left on 12 January 2026 for waters near Minamitori Island, about 1,900 km southeast of Tokyo. It recovered rare earth mud from about 6 km depth, the first continuous lift of such mud from that depth (Reuters via Marine Technology News, 2 February 2026). In July 2026 the government reported that about 50 tonnes of mud were recovered and that medium and heavy rare earths made up about 54% of the total rare earth content. Officials did not give the deposit size because the sampling was too limited. A month-long trial aiming to dredge 350 tonnes of mud a day is planned from February 2027, and an assessment of industrial prospects is due by March 2028 (Ocean Mining Intel, 28 July 2026).

The context is trade policy. Reuters reported that China banned exports of dual-use items to Japan in January 2026, including rare earths, which is why Japan funds the work. A trial is not a mine.

Terms used in nodule reports

Wet and dry tonnes. Nodules hold water. TMC states its application resource of 619 million tonnes in wet tonnes, with potential exploration upside of a further 200 million tonnes. Metal grades are usually quoted on a dry basis, so you must remove the water before applying a grade.

Grade. The percentage of a metal by weight. The ISA study’s mean dry grades are 1.34% nickel and 1.14% copper (dry weight).

Resource and reserve. A resource is an estimate of material that may be mined. A reserve is the part shown to be economic under current conditions. The ISA study estimates inferred resources, so its metal totals are not reserves.

Abundance. Nodules are measured in kilograms per square metre of seabed. The ISA study’s mean abundance in its screened data set is 7.2 kg per square metre, with a maximum of 44.1, so the ground is patchy.

What a nodule project’s metal could be worth

Use the calculator to see how output, grade and recovery combine. It uses the ISA study’s mean dry grades as defaults and assumes you supply prices, water content and recovery. It covers nickel and copper only, and it leaves out cobalt, manganese, operating costs, processing charges and royalties, so the result is gross value, not profit. TMC’s own resource figure is stated in wet tonnes, which is why water content is an input.

What satellites can and cannot see in seabed mining

Optical satellites cannot see through deep water, so they do not map nodule fields or the seabed. They can help at the surface: ship tracks, coastal ports and processing sites on land. Farmonaut works on land licences, where satellite data screens ground for mineral targets before drilling. That is an exploration target ahead of any resource estimate, and it does not cover the deep ocean. Our satellite mineral exploration page explains what the service does on land.

▶ Covers the limits of satellite mineral exploration that matter for due diligence. · 2:08

How to follow the story: what to check

• The ISA Council and Assembly outcomes: whether a mining code is adopted, and any change to the contractor list.
• The NOAA record for TMC USA: the draft environmental impact statement, the public comment period and the final decision.
• Independent monitoring results, such as the Nature Communications and Scientific Reports papers cited above.
• Company filings on SEC EDGAR: financing, permit assumptions and risk factors.
• Government decisions: Norway, the Cook Islands, the European Union and the countries calling for a pause.

We cover a connected topic in Machine to Separate Gold From Sand: 6 Types Compared.

Frequently asked questions

What is deep sea mining?

It means taking mineral deposits from the seabed at depths of roughly 3,000 to 6,000 metres. The main targets are polymetallic nodules, which hold manganese, nickel, copper and cobalt, plus sulphide deposits and cobalt-rich crusts (ISA contractor list).

Is seabed mining legal?

Exploration is legal under ISA contracts. Commercial mining in international waters needs rules the ISA has not adopted. The US uses its own 1980 law and NOAA permits, and other countries disagree with that route.

Which companies are doing deep sea mining?

The ones with the most advanced work are TMC, GSR (DEME Group) and Allseas as a machine builder, with Odyssey Marine Exploration and American Ocean Minerals planning a merger. None is producing metal.

Who manufactures underwater mining machines?

Machines are built per project by offshore contractors. Allseas built TMC’s pilot collector and riser, and GSR built Patania II. There is no standard product to order.

When could commercial seabed mining start?

TMC expects a US permit before the end of Q1 2027 and says production would follow. The ISA’s mining code is expected to take at least three to four more years to agree, according to Benchmark.

Which metals come from the seabed?

Nodules contain manganese, nickel, copper and cobalt. Rare earths are found in some seabed muds, which Japan is testing. They are not a main nodule metal.

How much of the world’s nickel and cobalt could nodules supply?

The ISA study estimates 270 million tonnes of nickel and 46 million tonnes of cobalt in its CCZ study area. That is a resource estimate, not a reserve, and how much could be recovered is untested.

What are the environmental risks?

The main findings so far are slow recovery of seabed animals (DISCOL, 26 years) and sediment plumes that settle mostly within a few hundred metres but are detectable up to 4.5 km away.

Can you invest in deep sea mining?

A few companies are listed, including TMC (Nasdaq: TMC) and Odyssey Marine Exploration (Nasdaq: OMEX). They have no seabed metal revenue. This is not investment advice.

Does seabed mining include rare earths?

Japan is testing rare earth mud near Minamitori Island. Nodule projects in the CCZ target manganese, nickel, copper and cobalt instead.

Can satellites help with seabed mining?

Not on the seabed itself. Satellites can watch the surface and land sites, while seabed work relies on ships, sonar and underwater vehicles.