International subsea cables consolidating Korea and overseas amount to less than one-third of Japan's. At home, competition to build artificial intelligence (AI) data centers and secure graphics processing units (GPUs) is fierce, but observers say the international networks consolidating them with overseas data centers are relatively weak.
◇ Korea has 9, Japan 31… gap in international networks
According to the report "Sovereign subsea optical cable infrastructure strategy for survival and prosperity in the AI era" by the National Information Society Agency (NIA) on the 11th, the number of international subsea cables that the three domestic telecom companies operate or are working to build totals nine, excluding overlapping routes.
A simple sum of routes by carrier comes to 11, but that figure counts APG and APCN-2, which KT and LG Uplus use jointly, as one route each. Japan, which NIA presented as a comparison, has 31 international subsea cables in total, combining 23 in operation and eight under construction. That is about 3.4 times Korea's. The United States has about 103, and Europe has about 152 international subsea cables, it was found.
Because each subsea cable route has different transmission capacity, it is hard to compare international network competitiveness between countries by count alone. Still, NIA assessed that Korea lacks both the number of cables and total transmission capacity compared with major countries, and that the consolidation paths are skewed toward certain countries and regions.
◇ Only two direct links to the U.S. and Europe… 67% of subsea cables concentrated in Busan
Many of the subsea cables Korea uses pass through Japan, China and Taiwan. Only two lines consolidate to the United States or Europe without transiting those countries. The number of landing countries consolidating to terrestrial networks is also concentrated in Busan. About 67% of domestic subsea cables converge in Busan. About 99% of international data communications travel via subsea cables.
Lee Seong-hun, director of the digital infrastructure safety division at the Ministry of Science and ICT, said, "If an earthquake or submarine landslide occurs in nearby waters, multiple lines could be damaged at the same time," and noted, "If independent bypass routes are lacking, data will pile onto the remaining lines, degrading the speed and stability of international internet and cloud services." Lee added, "To secure route diversification, five new subsea cables are being pursued by 2030."
Data traffic transiting Korea accounts for about 3% of the world. Unlike Japan and Singapore, which have become major data gateways in Asia, Korea remains on the periphery of international networks. If international networks are insufficient, even expanding domestic AI data centers and GPUs may have limited effect. That is why telecom companies have recently moved to expand subsea cable routes. KT operates five international subsea cables—NCP, APG, APCN-2, KJCN and TPE—and is working to build a new route, "ALPHA." SK Broadband has commercialized "SJC2," which consolidates Southeast Asia and Japan, and is building "E2A," linking Busan and California, with an opening targeted for 2028.
◇ More than 2 trillion won per route at most… "National investment should go in parallel"
Building a new international subsea cable requires massive expense and time. According to the industry, constructing a single route typically costs from 1.5 trillion to more than 2 trillion won, and it takes more than 10 years to recoup the investment. Construction costs have roughly doubled from the past as rising raw material prices and investment competition among global big tech companies overlap.
Complex permitting procedures are also cited as an obstacle to project progress. In the process of obtaining occupancy and use permits for public waters, consent from rights holders and environmental impact assessments are required, so the entire procedure can take more than 20 months. Maintenance and repair expense to respond to cable faults, earthquakes and cutting accidents is also increasing by about 5% annually.
Under this business structure, private investment inevitably concentrates on routes with higher profitability. Direct links to the United States and Europe or independent bypass networks, which are needed for national security and disaster response but offer lower profitability, are likely to be pushed down the investment priority list. NIA proposed that the government, telecom companies, large corporations and financial firms form a joint consortium to share construction costs and investment risk. Companies that need global networks—such as in AI, electronics, automobiles, aviation and logistics—would participate in cable construction, while the government would use some lines for public, security, diplomatic and research purposes.
Chae Hyo-geun, vice chair of the Korea IT Service Industry Association, said, "While the private sector should lead routes with higher profitability, government investment should go in parallel for direct links and bypass networks needed to secure national security and network resilience," and added, "We should see subsea cables not as an expense but as a long-term investment that expands the nation's digital territory."