NTT Forms JV for the $1 Billion Intra-Asia Marine Cable Project

NTT DATA has launched a joint venture to construct the Intra-Asia Marine Cable (I-AM Cable). With a total project cost of approximately $1 billion, this ambitious infrastructure project aims to create a next-generation communication backbone linking key economic hubs across East and Southeast Asia by early fiscal year 2029.

The newly formed joint venture, Intra-Asia Marine Networks Co., Ltd. (I-AM NW), will oversee the construction and operation of this 8,100-kilometer cable system. This venture represents a significant strategic investment in the physical infrastructure of the internet, designed to secure data routes, enhance regional digital resilience, and solidify Japan's position as a critical Asia-Pacific data hub.

Strategic Rationale and Geographic Architecture

The I-AM Cable is a direct response to the explosive growth of data traffic fueled by artificial intelligence, cloud computing, and digital transformation across Asian economies. With over 99% of intercontinental data traveling via submarine cables, securing robust and diverse pathways has become a paramount economic and strategic priority.

The I-AM Cable route is meticulously planned for maximum impact and resilience:

• Core Trunk: The primary pathway connects Japan directly to Malaysia and Singapore, two of Southeast Asia's most vital digital and financial centers.

• Extended Connectivity: The system branches to provide additional links to South Korea, Taiwan, and the Philippines, creating a comprehensive network that blankets the region's major tech economies.

• Japanese Resilience: Within Japan, the cable will land at three geographically diverse points: Minamiboso (Chiba), Shima (Mie), and Fukuoka. This multi-landing strategy is specifically engineered to safeguard against service disruptions caused by natural disasters, such as earthquakes and typhoons, which are prevalent in the region. The Fukuoka landing is of particular note, as it is being developed in coordination with new data center clusters to serve as an international telecommunications hub for western Japan.

Technical Ambition: A 320 Tbps Powerhouse

The I-AM Cable is not just another cable; it is a showcase of cutting-edge submarine fiber-optic technology designed for future scalability. The consortium plans to implement two key advanced technologies:

1. Space Division Multiplexing (SDM): This technology allows the cable to accommodate up to 16 fiber pairs (32 cores), significantly increasing the potential conduit for data within a single cable sheath compared to traditional designs.

2. Wavelength Selective Switch (WSS) Functionality: This enables the remote, flexible adjustment of bandwidth allocation across different routes. Operators can dynamically respond to shifting traffic patterns or new business demands without requiring physical intervention.

The combination of these technologies will give the I-AM Cable an initial design capacity of approximately 320 terabits per second (Tbps). This immense bandwidth is squarely targeted at serving the needs of hyperscale cloud providers, global technology giants, and telecommunications operators who require ultra-reliable, high-capacity connectivity.

A Consortium of Complementary Strengths

The formation of I-AM NW brings together three Japanese industrial leaders, each contributing unique and critical capabilities to ensure the project's success:

• NTT DATA: As a world-leading $30+ billion IT services and digital infrastructure provider, NTT brings unparalleled technical expertise in network engineering, a global client base, and deep experience in operating submarine cables. The company has established similar joint ventures for other major cable systems, including the MIST and JUNO cables.

• Sumitomo Corporation: This global trading and business investment giant contributes its extensive multinational network and business development prowess. Its participation, facilitated through an entity with Sumitomo Mitsui Finance and Leasing, will be crucial for navigating cross-border agreements and securing commercial partnerships across the cable's diverse landing countries.

• JA Mitsui Leasing: A specialist in leasing and asset financing, this partner provides the critical financial structuring and asset management expertise required for a capital-intensive, long-life infrastructure project. JA Mitsui Leasing has been building its portfolio in digital infrastructure, including a prior investment in the JUNO cable. JA Mitsui Leasing and NTT has partnered to create another joint venture, Seren Juno Network Co., Ltd. (“Seren Juno”), for the JUNO cable system.

Navigating Geopolitical Currents: How Geopolitics is Reshaping Asia's Subsea Cable Map

The planning of the I-AM Cable, a new $1 billion submarine cable connecting Japan to Southeast Asia, highlights a profound shift in the industry. While traditionally driven by technical and economic factors, subsea cable routing in Asia is now substantially influenced by geopolitical considerations, creating a complex new landscape for digital infrastructure.

The published route for the I-AM Cable reveals a deliberate strategy: it traverses the South China Sea while conspicuously avoiding areas within China's claimed "nine-dash line" and excludes any landing point in China. This is not an isolated decision but part of a broader industry trend where geopolitical risk mitigation is becoming a primary design constraint, often superseding technical optimization.

The "Avoidance" Strategy: A Costly New Norm

A growing number of Intra-Asia cable projects are adopting this cautious approach, accepting significant trade-offs to minimize exposure to geopolitical friction:

• AUG East, Candle, and Apricot Cables: Similar to the I-AM Cable, these systems have been routed to circumvent the contested nine-dash line.

• The Trade-offs: This strategy leads to tangible disadvantages, including higher capital and operational expenditures, longer cable routes, increased latency, degraded performance, and reduced overall competitiveness compared to more direct paths.

This represents a fundamental change in cable economics. Where the shortest, deepest-water route was once the undisputed goal, planners now explicitly factor in the long-term operational stability and political risk for their multinational customers.

The Alternative Path: Embracing Technical Optimization

In contrast, another cohort of cables continues to leverage the technically superior, deep-water routes through the South China Sea. These projects often involve a different consortium model, sometimes including Chinese partners, and have demonstrated strong commercial success by prioritizing performance:

• Asia Direct Cable (ADC): Activated in November 2024, this cable connects China, Japan, the Philippines, Singapore, Thailand, and Vietnam via an efficient route.

• Southeast Asia–Japan 2 (SJC2): Put into operation in July 2025, it links Japan, China, Hong Kong, South Korea, Singapore, and Vietnam.

• Commercial Success: Both ADC and SJC2 are reported to have achieved strong sales, underscoring the significant market demand for low-latency, high-capacity routes that technical optimization provides.

In addition to ADC and SJC2, there are multiple unannounced new subsea cable projects serving the Japan-Hong Kong-Singapore digital corridor, running through the preferred routes in the South China Sea, with or without the participation by Chinese operators and investors.