The city of Ulsan is developing an underwater data centre off its coast that could eventually house 100,000 servers. According to reports from Nikkei Asia, the project is led by Ulsan and the Korea Institute of Ocean Science and Technology (KIOST), with the facility planned to sit about 20 metres below the sea surface. The proposed facility would utilize seawater as the primary cooling medium, with Ulsan's coastal waters having an average annual temperature of about 13.3 degrees Celsius.
The project has received 40 billion won ($29 million) in central government funding over five years, as reported by Nikkei Asia. The broader development programme is budgeted at 51.1 billion won and aims to produce a standardised underwater data-centre model by 2030. The commercial phase is expected to begin after the demonstration programme, with Ulsan targeting construction of a larger underwater data-centre complex from 2031.
According to Nikkei Asia, KIOST research has suggested that seawater-based cooling could substantially reduce cooling-related electricity consumption. Earlier work on the Ulsan project estimated carbon reductions of about 12 per cent. The attraction lies in cooling being one of the biggest energy burdens in traditional data centres, with seawater providing a natural source of relatively cool water for dissipating heat from high-performance servers.
Ulsan is working with 12 industry, academic and research organisations, including KIOST, Ulsan National Institute of Science and Technology, POSCO, GS Engineering & Construction and SK Telecom. As reported by Nikkei Asia, SK Telecom is responsible for developing the AI GPU infrastructure and server-operation model. The project involves pressure-resistant enclosures, modular server and power systems and high-efficiency hybrid cooling technology.
According to CBRE Korea, data-centre power supply in the Seoul metropolitan area is expected to exceed 1,450 MW by 2028. Of 522 power-system impact assessment applications in the region, representing 33,592 MW of requested capacity, only 10 had received final approval by March 2026—an approval rate of just 1.9 per cent. South Korea is not alone in testing underwater data centres, with China already having an operational project and Microsoft previously testing subsea servers through its Project Natick.
