Japan's Tech Giants Launch $1 Billion Submarine Cable Venture to Connect Asia | I-AM Cable Project Signals Major Infrastructure Push
Project Overview: Introducing the I-AM Cable
On January 13, 2026, three major Japanese corporations announced a landmark joint venture to strengthen digital connectivity across Asia. NTT Limited Japan (a subsidiary of NTT Data Group), Sumitomo Corporation, and JA Mitsui Leasing have established Intra-Asia Marine Networks Co., Ltd. (I-AM NW) to build and operate a large-scale submarine communication cable system connecting Japan with Southeast Asia.
The project, named the Intra-Asia Marine Cable (I-AM Cable), represents a total investment of approximately $1 billion (150 billion yen), positioning it among the most significant digital infrastructure projects in the Asia-Pacific region. Commercial operations are scheduled to begin in early fiscal year 2029.
Technical Specifications and Scale
The I-AM Cable is designed as a state-of-the-art high-capacity communication infrastructure leveraging the latest fiber optic technologies.
Key Specifications
- Total Length: Approximately 8,100 km
- Design Capacity: Approximately 320 terabits per second (Tbps)
- Technology: SDM (Space Division Multiplexing) technology
- Fiber Capacity: Up to 16 fiber pairs (32 cores) per cable
- Landing Points: Japan (Chiba, Mie, and Fukuoka Prefectures), Malaysia, Singapore, and South Korea
- Future Connections: Philippines, Taiwan
The system incorporates Wavelength Selective Switch (WSS) functionality, enabling remote adjustment of wavelength bandwidth allocation across different routes. This allows operators to flexibly respond to changing business needs and traffic demands without physical intervention.
The Strategic Importance of Submarine Cables
The Backbone of the Digital Economy
Approximately 99% of international data communications travel through submarine cables. From video streaming and social media to cloud services and financial transactions, these undersea networks form the critical foundation of the modern digital economy.
The explosive growth of AI and machine learning applications, combined with surging data center interconnection demands, has driven unprecedented growth in international communication traffic across the Asia-Pacific region.
Japan's Geopolitical Advantage
Japan occupies a strategic position between Asian countries and the United States, serving as a crucial data hub for the Asia-Pacific region. However, in recent years, several cable projects have bypassed Japan, routing through Taiwan and the Philippines to Singapore instead—a trend industry observers have called "Japan Passing."
The I-AM Cable represents a strategic investment to maintain and strengthen Japan's position as Asia's data hub, ensuring the country remains central to regional connectivity architecture.
Disaster Resilience and Redundancy
The cable system features landing points in three Japanese prefectures—Chiba, Mie, and Fukuoka—to ensure high resilience against natural disasters affecting Japan's coastal waters. This distributed approach reflects lessons learned from the 2011 Great East Japan Earthquake, when multiple submarine cables along the Pacific coast were damaged, requiring six months for full restoration.
Fukuoka is being developed as a Western Japan international telecommunications hub, coordinating with newly planned data center clusters—a development that also supports regional economic revitalization efforts.
Economic Security Considerations
Submarine cables have evolved from simple communication infrastructure to critical national security assets.
Since 2024, submarine cable damage incidents have occurred near Taiwan and in the Baltic Sea, with some observers pointing to potential involvement by China and Russia. The Japanese government has responded by promoting cable route diversification under its "Digital Garden City Nation Infrastructure Development Plan" and strengthening support for related companies.
Japan's Ministry of Internal Affairs and Communications has set a target of increasing Japanese companies' global submarine cable market share from approximately 20% to 35% by 2030.
The Three Partners and Their Roles
NTT Limited Japan
As NTT Data Group's global ICT services provider, NTT brings decades of experience in building, selling, and operating major submarine cable systems including JUPITER, JUNO, MIST, and ASE. The company provides technical expertise and operational know-how.
Sumitomo Corporation
With 125 offices across 63 countries and regions, this global trading company brings extensive customer networks and business development capabilities. Sumitomo participates through an intermediate holding company established jointly with SMFL Mirai Partners, leveraging the combined customer bases and networks of both organizations.
JA Mitsui Leasing
Built on the foundations of the JA Group and Mitsui Group, this comprehensive leasing company brings financial structuring expertise. The firm has investment experience in information and communications infrastructure including mobile base stations, optical networks, and cloud/data center platforms. In 2022, JA Mitsui Leasing entered the submarine cable sector through its investment in JUNO, a cable connecting Japan and the U.S. West Coast.
Position in Japan's Digital Infrastructure Strategy
The I-AM Cable aligns closely with the Japanese government's digital infrastructure resilience policies.
Through the "Digital Infrastructure Development Fund," Japan's Ministry of Internal Affairs and Communications supports regional distribution of data centers, development of domestic submarine cables (particularly on the Sea of Japan side), and installation of international submarine cable branch lines. Diversifying landing stations beyond their current concentration on the Boso and Shima peninsulas is a key priority, making the Fukuoka landing strategically significant.
Japanese submarine cable suppliers, led by NEC, hold a position among the world's top three (alongside SubCom and Alcatel Submarine Networks). NEC's integrated domestic manufacturing capability provides significant economic security advantages, as the company can produce complete cable systems without relying on foreign suppliers.
Looking Ahead
I-AM NW will manage the entire value chain from cable planning through communication circuit sales, providing high-quality communication services to global technology giants and telecommunications operators across the region.
With the AI era driving explosive growth in ultra-high-speed, high-capacity data center interconnection demands, the success of the I-AM Cable may well determine whether Japan can establish itself as the definitive data hub of the Asia-Pacific region.
Japan is steadily advancing its digital infrastructure capabilities, but what about your country? How are submarine cables and international communication infrastructure being developed where you live? Share your thoughts in the comments!
References
- https://www.nttdata.com/global/en/news/press-release/2026/january/011300
- https://www.nikkei.com/article/DGXZQOUC1346K0T10C26A1000000/
- https://www.csis.org/analysis/strategic-future-subsea-cables-japan-case-study
- https://www.submarinenetworks.com/en/systems/intra-asia/i-am-cable/ntt-forms-jv-for-the-$1-billion-intra-asia-marine-cable-project
- https://www.mri.co.jp/knowledge/column/20250922.html
- https://journal.meti.go.jp/p/40663/
Reactions in Japan
A major 1.5 trillion yen investment. The combination of NTT and Sumitomo Corporation gives me confidence. JA Mitsui Leasing's financing capabilities shouldn't be underestimated either. Watching this as a long-term infrastructure investment.
320Tbps is among the largest in Asia. SDM technology adoption ensures future scalability. Technically, this is quite an ambitious project. Looking forward to completion.
So happy that Fukuoka will have a landing station! Hope it develops as a data center hub for Western Japan. Expecting this to contribute to regional revitalization.
A positive move from an economic security perspective. Securing routes that bypass China is geopolitically important. However, the question is how the international situation will change by 2029 launch.
My company also has a DC in Singapore, so I'm hoping for latency improvements. Better Japan-ASEAN communication quality directly impacts our work efficiency.
Another big corporate alliance. Will this 1.5 trillion yen mega-project be profitable? This is an era when Google and Meta are laying their own cables.
Distributed landing at 3 domestic sites is a design that incorporates lessons from the Great East Japan Earthquake. If Sea of Japan routes are also developed, communication infrastructure redundancy will greatly improve.
I hold NTT stock, but my impression is their overseas expansion has been tough. Need to watch if this project becomes a growth driver. Also watching related stocks.
I wonder if there's coordination with the Ministry's Digital Infrastructure Fund. Even if private-sector led, government support would increase competitiveness. Waiting for follow-up news.
There's definitely demand for connections to Malaysia and Singapore. If they're considering branches to Thailand and Vietnam, the future potential is high.
Environmental impacts of submarine cables aren't discussed much, but I hope they consider the effects of installation work on the seabed environment. We need sustainable infrastructure development.
Will this improve lag when playing on Asian servers? For esports, ping differences in international tournaments are a matter of life and death.
Submarine cable business requires massive initial investment with long payback periods. The key is securing long-term contracts with hyperscalers. Expecting NTT's sales capabilities.
Japan-originated submarine cables to Asia could serve as a counterbalance to China's Digital Silk Road initiative. Perhaps coordination within the Quad framework is also in view.
In the AI era, international communication bandwidth becomes a bottleneck. This kind of infrastructure investment is also positive for Japanese startups. A foundation for seamless global expansion.
I wonder if they'll land at other places in Mie Prefecture besides Shima? Want to know more details. Also hoping for economic benefits to the local area.
Working in Singapore's tech industry. A new direct route to Japan is welcome. If latency between Tokyo and Singapore improves, it will lead to better cloud service quality.
From an Australian perspective, Japan strengthening its position as Asia's data hub is good news. We're also working on improving Indo-Pacific connectivity through Quad cooperation.
Glad that Korea is included as a landing point. Strengthening Japan-Korea communication infrastructure should benefit both countries' IT industries. Technical cooperation should proceed regardless of political tensions.
A big opportunity for Malaysia. If digital infrastructure is strengthened through partnership with Japanese companies, it will also help attract foreign investment. Hope this leads to ASEAN-wide development.
Work at a US cloud company. Japan's investment in Asia-bound cables aligns with our APAC expansion strategy. More options for data center interconnection is very welcome.
Looking forward to future branch connections to Vietnam. Our IT industry is growing rapidly, and high-quality international communication infrastructure is essential. We welcome technical cooperation with Japan.
As a Hong Kong analyst, it's clear this cable bypasses China. A project with strong geopolitical implications, but one that also meets market demand.
Great that connection to the Philippines is in future plans. Stable international communications is a lifeline for our BPO-heavy country. Looking forward to improved connectivity with Japan.
As a UK infrastructure investor, I'm watching the Asian submarine cable market closely. This Japanese consortium project appears to have a solid, risk-diversified investment structure.
It's reassuring that connection to Taiwan is planned. With cross-strait tensions, diversifying communication routes is important for security as well. We welcome cooperation with Japan.
From India's perspective, Japan's infrastructure investment in Asia is a welcome move. As a Quad member, we also want to contribute to strengthening Indo-Pacific digital connectivity.
From the German telecom industry perspective, the Asian cable market is rapidly growing. Strengthening Europe-Asia connectivity is also a future challenge. Japan's moves are informative.
As a Wall Street analyst, I have questions about the profitability of a $1B project. In an era when GAFA are laying their own cables, watching whether the consortium model can remain competitive.
From New Zealand's view, Japan maintaining its position as Asia's communication hub is important for Pacific regional connectivity overall. Looks like a good model for regional cooperation.
As a Japanese-American, I'm proud of my home country's infrastructure investment. Interest in strengthening Japan's digital competitiveness is growing in Silicon Valley too.