Japan and Korea AI Infrastructure: SoftBank, Sakura, SK — 2026-09-11

Top developments

SK Group Chairman Chey Tae-won Visits Ulsan AI Data Center

On September 10, 2026, SK Group Chairman Chey Tae-won made his first visit to the SK AI Data Center in Ulsan since construction began in August 2025. The facility, valued at approximately 7 trillion won ($5.3 billion), is slated to begin operations in the second half of 2027. This visit underscores SK’s commitment to establishing Ulsan as a core hub for Korea’s AI industrial ecosystem, with local media noting the site is intended to be the "foundation of Korea's AI development."

SoftBank Repays $40 Billion Bridge Loan for OpenAI Stake

On September 9, 2026, SoftBank Group Corp. announced it would repay the balance of a $40 billion bridge loan originally signed to finance its investment in OpenAI. The conglomerate is moving to refinance this deal with longer-term debt, a strategic shift that stabilizes its capital structure as it continues to fund massive AI infrastructure projects like Project Stargate and domestic Japanese GPU clouds.

Naver Cloud Highlights "4,000 GPU" Security Strategy

In an interview published on September 10, 2026, Naver Cloud executives detailed their strategy to build a "national security AI shield" using 4,000 GPUs. The company emphasized that relying on overseas models for state-level cyber security is untenable, positioning its proprietary infrastructure and large language models as essential for sovereign AI capabilities in Korea. This aligns with the Ministry of Science and ICT’s broader push for domestic compute capacity.

Stargate Korea Plans Stall Amid Power and Funding Hurdles

Reports from September 7, 2026, indicate that the Stargate Korea project involving OpenAI, Samsung, and SK has stalled nearly a year after its announcement. Key issues regarding site selection, power supply agreements, and final funding structures remain unresolved, contrasting with the rapid progress of Stargate sites in the US and other regions. This delay highlights the regulatory and infrastructural challenges facing hyperscale AI buildouts in South Korea.

Local view

Korea Herald & KMI Daily (South Korea): Local coverage focuses heavily on the tangible progress of physical infrastructure. Korea Herald reported on SK Telecom’s spin-off of its AI data center business into "SK Horizon," securing investments from global private equity firms KKR and IMM, aiming to accelerate decision-making and focused investment. KMI Daily emphasized Chairman Chey’s direct involvement in the Ulsan site, framing it as a symbolic commitment to the government’s national AI goals.

Nikkei (Japan): While no specific new Japanese infrastructure announcements emerged in the last 7 days, Nikkei continues to track the broader context of Japan’s $60 billion investment target and the role of SoftBank’s "Neocloud" strategy. Recent articles highlight the competitive pressure from Korea’s aggressive GPU procurement and the importance of METI subsidies for domestic players like Sakura Internet.

Context & numbers

• Ulsan AI Data Center: 7 trillion won (~$5.3 billion) investment; operational start targeted for H2 2027.
• SoftBank/OpenAI Financing: $40 billion bridge loan repaid/refinanced as of Sept 9, 2026.
• Naver GPU Capacity: 4,000 GPUs dedicated to national security AI initiatives.
• Korea MSIT Subsidies: Approximately KRW 1.46 trillion ($1.1 billion) allocated for 13,000 high-performance GPUs across Naver Cloud, NHN Cloud, and Kakao (policy context from May 2026, still active).

On the radar

• Stargate Korea Resolution: Watch for official statements from OpenAI, Samsung, or SK regarding the stalled site selection and power agreements for the Korean Stargate campus.
• SK Horizon Integration: Monitor the operational integration of SK Broadband’s AI data center business into the newly launched SK Horizon entity, particularly its capital expenditure plans following the KKR/IMM investment.