Most advanced deployed
Highlander / Hainan
Operational · 100 pods planned
China’s Hainan underwater AI center went live in February 2025. It is the strongest evidence of repeatable, modular subsea deployment.
China has the only scaled, operating subsea data centers; Panthalassa leads the startup race
The field spans at least 30 developers, operators and industrial partners, but only China’s Hainan and Shanghai projects have crossed into multi-module or commercial operation. Among venture-backed companies, Panthalassa is furthest ahead after two sea trials and $140m raised; most floating-data-center programs remain in engineering or planning.
2
scaled operating projects
24 MW
Shanghai commercial design
$140m
Panthalassa raised
30+
organizations in the field
How far the leaders have progressed
Evidence-based maturity, not market valuation
blue operating · lighter blue earlier
Three leaders, for different reasons
Commercial-scale leader
HiCloud / Shanghai consortium
24 MW · offshore-wind linked
The Lingang project is described as in commercial operation. HiCloud, China Communications Construction and China Telecom appear in overlapping developer/operator roles.
Leading venture-backed startup
Panthalassa
$140m raised · Ocean-3 next
It completed Ocean-1 and Ocean-2 sea prototypes and targets commercialization in 2027. Reporting identifies Peter Thiel as the investment lead.
What the evidence says
- Deployment leadership is Chinese. Hainan is operational and Shanghai’s 24MW installation is reported in commercial operation. chinadaily.com.cn · marineinsight.com
- Panthalassa has the clearest startup financing and test record. Sources report $140m led by Peter Thiel and an Ocean-2 trial off Washington, with commercial systems targeted for 2027. finance.yahoo.com
- Nautilus proved a sizeable floating facility, but momentum weakened. Its Stockton barge reached 6.5MW and operations, yet was put up for sale in 2024. cloudcomputing-news.net
- The next wave is shipyard-led. Samsung/Mousterian, MOL/Kinetics/Hitachi, Seatrium and Keppel have 25–73MW designs or projects, but these trail live Chinese facilities. gcaptain.com · oedigital.com
Comprehensive company and project shortlist
| Organization / group | Type | Approach / capacity | Current evidence | Startup capital / leads | Source |
|---|---|---|---|---|---|
| Beijing Highlander / COOEC / Sinnet | Chinese public/industrial group | Subsea; 100 pods planned | Hainan operational; further construction | n/a | datacenterdynamics.com |
| Shanghai HiCloud / Hailanyun; CCCC; China Telecom | Private + state/public partners | Subsea + offshore wind; 24MW | Commercial operation | Not disclosed | people.cn |
| Nautilus Data Technologies | Private company | Waterborne barge; 6.5MW | Operated; asset put up for sale in 2024 | $100m reported; lead not established | cloudcomputing-news.net |
| Microsoft + Naval Group | Public + industrial partner | Seabed capsule; 855 servers | Successful Natick pilot; shelved | n/a | microsoft.com |
| Panthalassa | Startup | Wave-powered floating nodes | Ocean-1/2 tested; Ocean-3/commercial target 2027 | $140m; Peter Thiel reported lead | singularityhub.com |
| Subsea Cloud | Startup | Underwater; proposed 13,500 servers | Permits/claims reported; operating status not independently clear | Not disclosed | datacenterdynamics.com |
| NetworkOcean | Startup | Underwater; 500kW | San Francisco Bay test planned | Not disclosed | gizmodo.com |
| Atomarine | Startup | Offshore barges; 75–100MW modules, ~450MW vision | Natural-gas pilot targeted 2028 | Amount not disclosed; Y Combinator backer | dealroom.co |
| Samsung Heavy Industries + Mousterian | Public + private developer | Floating; first 50MW, designs to 200MW | Engineering contract and class approvals | Mousterian funding not disclosed | gcaptain.com |
| MOL + Kinetics/Karpowership + Hitachi | Public + subsidiaries | Converted ship / powership; 73MW | In development; 2027 deployment planned | n/a | dailysabah.com |
| Seatrium | Public | Jetty-moored barge; 30MW | Approval in Principle, July 2026 | n/a | oedigital.com |
| Keppel Data Centres | Public-company subsidiary | Floating modular park; reported 25MW | Plans / early work; 2028 target reported | n/a | thetechcapital.com |
| Mocean Energy | Private company | Blue Core: wave/solar/battery floating AI racks | Concept / pre-Series A development | Raising £5m; not counted as raised | dailybusinessgroup.co.uk |
| Optimal Transit | Joint venture | Kraaken floating platform; 10/100MW | Unveiled concept | Not disclosed | idcnova.com |
| DeepGreen Cook Inlet SPV | Private SPV | Underwater, Alaska | Preliminary environmental/engineering application | Not disclosed | adn.com |
| KIOST + POSCO + GS E&C + SK Telecom | Research/public/private consortium | Underwater complex; 100,000-server ambition | Research agreement / planning | n/a | datacenterdynamics.com |
| NTT Facilities + Eurus + MUFG + NYK | Japanese consortium | Floating, solar + batteries | Pilot announced | n/a | enlit.world |
| Denv-R | Private company | Small floating container, Nantes | Demonstrator deployed | Not disclosed | cloudcomputing-news.net |
| Aikido Technologies | Private company/startup | Offshore wind + modular AI data center | Concept / early entry | Not disclosed | datacenterdynamics.com |
Method: web scan conducted 25 Aug 2026 across 1,900+ unique search results; 48 extracted organizations were normalized into project groups and filtered to builders, operators and material development partners. “Advanced” ranks demonstrated operation first, then sea trials, engineering/construction, approvals and concepts. Funding means cumulative startup capital reported by sources, excluding project finance; blank or “not disclosed” means no reliable amount surfaced.