How underwater data center cooling works? Servers generate heat Thousands of servers process data and AI workloads, producing heat that must be removed to prevent overheating. Heat transfers to seawater Inside the sealed module, a heat exchanger transfers heat from the server cooling system to seawater. Depending on the design, seawater may flow through cooling pipes or directly through dedicated heat-exchange equipment. Seawater carries heat away The warmed water is discharged back into the ocean, where currents help disperse the heat. The relatively cool surrounding water continually absorbs more heat. Data and electricity travel through cables Subsea cables connect the module to shore for power and data transmission. The sealed enclosure protects the servers from seawater and external pressure. DOCUMENTED CASE STUDIES OF UNDERWATER DATA CENTERS Microsoft Project Natick Location Orkney Islands, Scotland, United Kingdom Approach Seawater-based heat exchange in a sealed underwater data center Details Microsoft deployed its Northern Isles data center on the seabed in 2018 and operated it for two years. The system was retrieved in 2020 for analysis, and Microsoft reported that its servers had an eight-times lower failure rate than the land-based comparison group. Key Takeaway Underwater cooling can support reliable server operations and reduce reliance on conventional cooling infrastructure, although Microsoft later discontinued the project rather than commercializing it. Source: Microsoft — Project Natick results Hainan Underwater Data Center Location Offshore Lingshui, Hainan Province, China Approach Natural seawater cooling in sealed underwater computing modules Details The commercial facility began operations in March 2023 and expanded in February 2025 with a new underwater module capable of housing more than 400 high-performance servers. The computing cluster supports AI model training and inference, industrial simulation, game development and marine research while using seawater to dissipate heat. Key Takeaway Hainan demonstrates the commercial application of seawater-based cooling for high-performance computing, including AI workloads, while reducing dependence on freshwater for cooling. Source: State Council of China — Underwater intelligent computing cluster Share this article