Status reflects May 11, 2026. Operational = paying customers and verified deployment. Hardware deployed = pods in water, commercial status unconfirmed. Funded = financed but not built. Concept = announced, no deployment. Contested = filed but facing organized local opposition. Decommissioned = the program ended.
🇺🇸 Microsoft Research, US · Decommissioned Decommissioned 2024
Project Natick
Phase 1: Pacific off San Luis Obispo, CA (2015). Phase 2: European Marine Energy Centre, Orkney Islands, Scotland, 36m depth (2018–2020).
864 servers in a 12.2-meter sealed steel cylinder, nitrogen-filled, cooled passively by surrounding seawater, powered by tidal + wind. 25-month operation ended July 2020 with recovery; program formally ended June 2024. Recorded one-eighth the failure rate of an identical onshore control. Microsoft cited the inability to swap GPUs in sealed pods as the core blocker for the AI era.
240 kW IT load
1/8× server-failure rate vs. land
25 months on the seafloor
🇨🇳 Highlander Digital + HiCloud, China · State-aligned Operational
Highlander Hainan UDC
Lingshui Li Autonomous County, off Hainan Island, ~35m depth, South China Sea. Module 1 deployed March 2023; Module 2 +400 servers February 2025.
First commercial subsea data center on the public record. Each 1,300-tonne capsule holds 24 racks / ~400–500 servers; cluster targeted at 100 capsules with a long-term 500 MW plan. Cooling is passive seawater. Power is onshore grid via submarine cable. Deployed by COOEC, the offshore engineering arm of state oil major CNOOC.
1,300-tonne capsules
~30,000 PC compute today
500 MW long-term target
🇨🇳 Shanghai HiCloud, China Sunk Oct 2025
HiCloud Shanghai Offshore (Lin-gang)
10 km off Shanghai's eastern coast, 10m depth, East China Sea.
First wind-paired commercial subsea data center anywhere. Installed October 2025; cluster ramp scheduled through 2026. 24 MW planned at $232M (¥1.6B) investment. 97% of power comes from the adjacent offshore wind farm. Target PUE 1.15. This is the operational template every other operator is now studying.
24 MW planned
97% wind-powered
PUE 1.15 target
🇺🇸 Nautilus Data Technologies, US Operational
Nautilus Stockton 1
Port of Stockton, San Joaquin River, California. Freshwater, moored barge. Operating since 2021.
The only commercially operating floating data center in the United States. 6.5 MW critical IT across four vaults. Once-through river water on primary loop, vacuum-sealed secondary; ASHRAE A1. Certifications: ISO 27001, SOC 2 Type 2, HIPAA, NIST 800-171. Grid tie via Port of Stockton.
6.5 MW critical IT
Freshwater cooling
~70% less water vs. inland evaporative
🇺🇸 DeepGreen Western Passage LLC, US Contested
DeepGreen Eastport (proposed)
Western Passage, off Eastport, Maine. 27 acres of tidal seabed. FERC preliminary permit filed February 11, 2026.
51 MW tidal-powered subsea AI complex: 170 tidal turbines + 34 data pods, $415M, backed by a Needham, Massachusetts real-estate developer with no marine operations experience. Passamaquoddy Tribe (Sipayik) and Down East lobster + scallop fishermen mobilized immediately. Maine LD307 — a statewide data-center moratorium running through November — cleared the legislature on April 14, 2026; Gov. Janet Mills vetoed it on April 24 over a single carveout dispute (the Jay paper mill), then signed an Executive Order on April 29 standing up the data-center advisory council the bill would have created. The bill is the first U.S. statewide data-center moratorium to clear a legislature; the EO is the operative regulatory pause.
51 MW proposed
$415M capex
60 days from filing to state moratorium
🇺🇸 Subsea Cloud, US · Founded 2021 Hardware deployed
Subsea Cloud Jules Verne + Njord01 + Manannan
Jules Verne: Port Angeles, WA, ~9m depth, Salish Sea. Njord01: Gulf of Mexico (250m target, concept). Manannan: North Sea (200m target, concept).
U.S. private-sector challenger. 20-foot containers, 16 racks / ~800 servers / ~1 MW per pod. Pressure-equalized dielectric fluid instead of a sealed nitrogen interior. 100 Gbps fiber + power cable to shore. Pilot pod claimed deployed; commercial paying-customer count has not been confirmed publicly since 2023. Flag as opaque.
~1 MW per pod
100 Gbps fiber to shore
Status: unverified
🇯🇵 MOL × Kinetics (Karpowership), Japan + Türkiye Funded · Conversion 2026
MOL Floating DC Powership
120-meter converted Mitsui O.S.K. Lines vessel, paired with a powership for off-grid generation. MoU July 7, 2025; Hitachi joined April 2026.
Modular subsea racks at 20 MW per module, scalable to 73 MW per vessel. Floating data center plus an attached generation ship that can dock at any port deep enough to accept it. Conversion 2026, first operations 2027. This is the model that escapes coastal-state jurisdiction entirely: a data center that can sail away.
73 MW per vessel
Mobile jurisdiction
2027 first ops
🇰🇷 Samsung Heavy Industries × OpenAI · LoI Oct 2025 Concept
Stargate Floating DC
Concept hull only. Sister project to Stargate's land buildout in South Korea.
Letter of intent October 2025; conceptual ship model unveiled. The headline claim is 1.5 GW within 36 months. No hull exists yet. Tracking because if Samsung Heavy ships even 10% of that capacity, it changes the regulatory conversation about floating data centers globally. Until then, the claim sits in the same bucket as gigawatt-class orbital data center pitches.
1.5 GW headline claim
36 months to delivery (claimed)
No hull yet
Roster methodology
Projects qualify if they are named, cited in primary sources, and physically located in or on water (subsea, floating, or coastal-adjacent submerged). Six additional projects we are aware of (NetworkOcean, NYK Yokohama mini-float, Nautilus Limerick, Nautilus Millinocket pivot, NEOM Oxagon, Norwegian wave-energy concept) are tracked at lower confidence and will be promoted as evidence consolidates. If you operate a project not listed here, write us.
