Reviewed August 2026 against the International Seabed Authority’s exploration-contract registry, The Metals Company’s and Odyssey Marine Exploration’s Nasdaq/SEC filings, and Deep Ocean Resources Development Co., Ltd.’s corporate ownership disclosure.

Try it: Run your own numbers →

Deep Sea Mining Companies: The Stocks That Actually Trade

Only a small slice of the entities called “deep sea mining companies” are stocks you can actually buy. As of August 7, 2026, there is exactly one pure-play seabed-mining stock on a major U.S. exchange — The Metals Company (NASDAQ: TMC), trading at $4.57 with a $1.98 billion market cap — plus one merger in progress, Odyssey Marine Exploration (NASDAQ: OMEX), which is folding into American Ocean Minerals Corp in a roughly $1 billion deal targeted to close in the second or third quarter of 2026 and re-list as Nasdaq: AOMC.

Nearly everyone else you’ll see described as an “undersea mining company” or “ocean mining company” — DORD, GSR, Interoceanmetal Joint Organization, China Minmetals — is a government agency, a majority state-owned contractor, or a private subsidiary with no separate ticker at all. This page walks through which is which, what each one actually controls on the seafloor, and how to check whether any of it has changed by the time you’re reading this.

Table of Contents

1. What “Deep Sea Mining Company” Actually Means
2. How Big Is the Marine Mining Market, Really
3. Deep Sea Mining Companies You Can Actually Buy
   • The Metals Company (TMC)
   • Odyssey Marine Exploration → American Ocean Minerals
   • Nautilus Minerals: The Cautionary Predecessor
   • Try it: Run your own numbers
4. The Contractors You Can’t Buy
   • DORD and Its Shareholders
   • GSR and DEME Group
5. The Rules That Decide Whether Any of This Ships
6. Tool: What Is a Nodule Deposit Actually Worth?
7. Farmonaut’s Role in Site and Fleet Monitoring
8. Frequently Asked Questions

What “Deep Sea Mining Company” Actually Means

“Deep sea mining,” “deepsea mining,” “undersea mining” and “ocean mining” all describe the same three deposit types: polymetallic nodules lying loose on the abyssal seafloor at depths of roughly 4,000–6,000 meters; cobalt-rich ferromanganese crusts coating seamounts; and seafloor massive sulfides clustered around hydrothermal vents. Nodules — potato-sized rocks rich in nickel, copper, cobalt and manganese — are the deposit type every company profiled below is actually chasing.

The International Seabed Authority (ISA), the UN body that administers mineral rights in international waters under the UN Convention on the Law of the Sea, publishes the full list of who holds exploration rights to those deposits. For polymetallic nodules alone, its registry lists 19 exploration contracts as of this review, spanning three ocean regions — a number that changes as the ISA Council extends or awards new licenses, so check the ISA’s live contractor list rather than treating this count as fixed. The extraction hardware behind nearly all 19 — riser-and-lift collector systems, AI-assisted seafloor mapping, remotely operated vehicles — is converging on similar designs; our rundown of mining-tech innovations covers the ROV and sensor specifics in more depth.

How Big Is the Marine Mining Market, Really

Fortune Business Insights sizes the global marine mining market at $4.6 billion in 2025, rising to $6.18 billion in 2026 and projected to reach $65.56 billion by 2034 — a 34.34% compound annual growth rate over that period — per the firm’s report, last updated July 20, 2026 (Fortune Business Insights, Marine Mining Market).

Before you quote a “marine mining market” figure anywhere, check exactly which activities a report counts. Different research firms scope the term differently: some include offshore sand, gravel and aggregate dredging alongside seabed metal extraction, others count only metallic-mineral projects, and the headline numbers can differ by a factor of two or more depending on which definition is used. Read the report’s scope section before citing its top-line figure — that single check would have prevented most of the conflicting numbers you’ll find searching this term.

Deep Sea Mining Companies You Can Actually Buy

This is the direct answer to “deep sea mining companies stock,” “deep sea mining stocks” and “deep sea mining stock“: as of August 2026, two tickers give you direct exposure, and one of those two is mid-merger. Everything else in the sector — GSR, DORD, and the sixteen other ISA-registered contractors — sits inside a parent company you can’t isolate, or isn’t tradable at all.

The Metals Company (TMC): The Nasdaq Vanguard

TMC began as DeepGreen Metals and moved onto the Nasdaq Global Select Market on September 10, 2021 through a SPAC merger with Sustainable Opportunities Acquisition Corp. Its two operating subsidiaries — Nauru Ocean Resources Inc. (NORI) and Tonga Offshore Mining Limited (TOML) — hold ISA exploration contracts in the Clarion-Clipperton Zone, sponsored respectively by Nauru and Tonga.

TMC is also running a second, parallel track through U.S. domestic law. On April 25, 2025, an Executive Order titled “Unleashing America’s Offshore Critical Minerals and Resources” directed the Commerce Secretary to expedite permitting under the Deep Seabed Hard Mineral Resources Act (TMC investor relations, Apr 25, 2025 release). Four days later, TMC USA filed the first-ever commercial recovery permit application under that statute — area TMC USA-A_2, 25,160 km² — alongside two exploration license applications (TMC USA-A and USA-B) covering a combined 199,895 km². TMC’s own resource estimate for those license areas, built from roughly 1,635 million wet tonnes of nodules, works out to approximately 15.5 million tonnes of nickel, 12.8 million tonnes of copper, 2.0 million tonnes of cobalt and 345 million tonnes of manganese. NOAA reported in March 2026 that it had found TMC USA’s consolidated application in “substantial compliance” with the statute’s filing requirements — a procedural finding, not a granted permit.

Odyssey Marine Exploration → American Ocean Minerals

Odyssey Marine Exploration (NASDAQ: OMEX) is not staying Odyssey Marine Exploration. It has a definitive merger agreement with American Ocean Minerals Corporation, structured as a roughly $1 billion pro forma deal, backed by $75.6 million in bridge financing completed in February 2026 and a $156 million private placement (PIPE) — over $230 million in combined equity capital, per the SEC filing (Odyssey Marine 8-K, reported via StockTitan). The combined company controls licensed and targeted seabed area exceeding 500,000 km², including two of three exclusive exploration zones in the Cook Islands and areas under U.S. regulatory jurisdiction, and targets polymetallic nodules for nickel, cobalt, copper, manganese and rare earths. The deal is expected to close in the second or third quarter of 2026, after which the stock trades as American Ocean Minerals Corporation on Nasdaq under “AOMC,” following a planned 25-for-1 reverse stock split.

Nautilus Minerals: The Cautionary Predecessor

Nautilus Minerals is the reason every company above talks so much about risk management. Once listed in Canada and Australia, Nautilus tried to mine seafloor massive sulfides in the Bismarck Sea off Papua New Guinea — copper, gold, silver and zinc, not nodules — and built the first purpose-designed seafloor production tools before running out of capital and filing for bankruptcy in 2019. Its engineering legacy shows up in ROV and riser designs used by later entrants; its financial collapse is the reason investors now ask how a project is funded through first commercial output, not just through the pilot stage.

The Contractors You Can’t Buy

Search “underwater mining companies” or “sea mining companies” and most of what surfaces isn’t a stock at all — it’s one of the government bodies, joint state ventures, or private consortiums that actually hold the majority of ISA seabed rights. The full polymetallic-nodule registry, as published by the ISA, lists these 19 contractors:

Source: ISA exploration-contract registry, checked August 2026 — verify the current list at isa.org.jm/exploration-contracts/polymetallic-nodules before relying on this snapshot, since contracts are periodically extended or added.

DORD and Its Shareholders

If you searched “Deep Ocean Resources Development Co., Ltd. shareholders” directly, here is the answer: DORD is majority state-owned. Incorporated on September 16, 1982, it is owned 75.83% by JOGMEC (Japan Organization for Metals and Energy Security, Japan’s state resource-security agency) with the remaining 24.17% held across 43 private-sector companies, including six non-ferrous metal firms, according to DORD’s own corporate profile (DORD company profile). DORD holds Japan’s only ISA exploration contract for polymetallic nodules, signed June 20, 2001 and extended in 2021, in the Clarion-Clipperton Zone. Because JOGMEC’s stake is not itself traded, there is no public way to buy into DORD; you’d need exposure to one of its 43 minority shareholders individually, and DORD does not publish that shareholder list.

GSR and DEME Group

Global Sea Mineral Resources NV is the deep-sea exploration unit of Belgium’s DEME Group NV, which listed on Euronext Brussels under ticker “DEME” on June 30, 2022, with 25,314,482 ordinary shares priced at €96 apiece for an initial market capitalization of €2.43 billion. GSR itself carries no separate share price — buying DEME buys all of DEME’s dredging and offshore-energy business, not a pure seabed-mining bet. GSR holds three ISA exploration licenses for nodules in the Clarion-Clipperton Zone and the Cook Islands EEZ. Nodule fields in that zone average roughly Ni 1.3%, Co 0.2%, Cu 1.2% and Mn 27% by weight, per the International Manganese Institute’s profile of GSR’s operating area.

The Rules That Decide Whether Any of This Ships

None of the stock or market-size figures above matter if the underlying permits never convert into commercial output — and that decision runs through two separate, unfinished rulebooks.

The ISA Mining Code: exploration regulations already exist, but the exploitation regulations that would let a contractor sell nodules commercially are still in draft. The Council concluded Part I of its 31st Session on March 19, 2026, in Kingston, Jamaica, after nine days of talks; delegates worked through 29 of the 32 outstanding issues on the Secretariat’s list, reached agreement in principle on an Equalisation Mechanism and a Compliance Committee, and approved extensions to six existing exploration contracts. Part II reconvenes in July 2026 (ISA Council 31 outcome, Mar 2026). Check the ISA’s own Mining Code page before assuming this status is still current — it is renegotiated at every Council session.

The U.S. domestic track: because the United States never ratified UNCLOS, it runs a parallel licensing system through NOAA under the 1980 Deep Seabed Hard Mineral Resources Act. The April 25, 2025 Executive Order directed NOAA to expedite that process; TMC USA’s applications (above) are the first real-world test of it. Whichever track finishes its rulebook first — ISA’s multilateral code or NOAA’s unilateral one — will likely set the terms every other contractor on the registry table above has to work within.

How to check the current status yourself: (1) open the ISA Mining Code page linked above and read the “latest session” summary; (2) search NOAA’s Office of Ocean Exploration and the Federal Register for “TMC USA” or “Deep Seabed Hard Mineral Resources Act” for permit-stage filings; (3) check each contractor’s ISA registry entry for contract expiry and extension dates, since exploration contracts run in fixed terms and lapse if not renewed.

Tool: What Is a Nodule Deposit Actually Worth?

Plug in a tonnage estimate and metal grades from any contractor’s filing — GSR’s and TMC’s cited above are good starting points — to see the gross in-situ metal value before extraction, processing or ISA payments are subtracted.

Assumes 100% metal recovery from the stated grades and today’s input prices held flat; it excludes extraction cost, processing losses, ISA royalties or equalisation payments, and shipping — all of which reduce the realized value well below this gross figure. Default grades reflect the Clarion-Clipperton Zone averages cited above; swap in a contractor’s own filed figures for a project-specific estimate.

Farmonaut's Role in Site and Fleet Monitoring

Farmonaut isn't a seabed contractor — its satellite platform supports the monitoring work that sits around mining and infrastructure projects on land and at the coast: site health tracking, carbon footprint tracking, blockchain traceability for mineral supply chains, and fleet management for the vessels and equipment that support offshore operations. These tools apply to the onshore processing, port logistics and terrestrial exploration work that surrounds every company profiled above, even though the seabed collection itself happens well beyond satellite optical range.

APIs for integration: Farmonaut API  |  Developer Docs  |  large-scale project dashboards at sat.farmonaut.com.

Frequently Asked Questions

• Which deep sea mining companies are publicly traded?
  Two: The Metals Company (NASDAQ: TMC) outright, and Odyssey Marine Exploration (NASDAQ: OMEX), which is merging into American Ocean Minerals Corp and will trade as Nasdaq: AOMC once the deal closes. GSR sits inside DEME Group (Euronext Brussels: DEME) with no separate ticker; DORD is 75.83% state-owned and not listed anywhere.
• Who owns Deep Ocean Resources Development Co., Ltd.?
  JOGMEC (Japan Organization for Metals and Energy Security) holds 75.83%, and 43 private Japanese companies hold the remaining 24.17%, per DORD's own corporate profile.
• How big is the marine mining market?
  Fortune Business Insights puts it at $6.18 billion in 2026, forecast to reach $65.56 billion by 2034. Check the report's scope definition before comparing that figure to a different firm's number — narrower and broader definitions of "marine mining" produce very different totals.
• What minerals do these companies target?
  Mainly nickel, copper, cobalt and manganese from polymetallic nodules, plus copper, gold, silver and zinc from seafloor massive sulfides at sites like Nautilus Minerals' former Bismarck Sea project.
• Is deep sea mining actually legal yet?
  Exploration is; commercial exploitation isn't fully authorized under either rulebook that governs it. The ISA's exploitation regulations remain in draft as of its March 2026 Council session, and NOAA's parallel domestic permitting process for TMC USA had reached only a "substantial compliance" finding, not a granted permit, as of that same period.

---

The company list above will be out of date within a year — new ISA contracts get awarded, exploration licenses lapse or extend, and mergers like Odyssey's close or fall through. The registry table, the ISA Mining Code page, and each company's own investor-relations page are the three places to re-check before making any decision based on this article.