AdvantageJul 16, 2025 9:00:00 AM5 min read

Under the Sea, Over the World: Exploring Subsea Cable Networks

Submarine cable networks serve as the backbone of the global internet, facilitating international transactions, video conferences, cloud deployments and much more. This sprawling web of subsea cables in the dark depths of the ocean seamlessly supports billions of daily online data exchanges.

While these underwater lifelines are powerful and efficient, they come with serious risks. To mitigate these risks and procure and manage submarine infrastructure effectively, organizations must leverage deep technical expertise to plan strategically.

This article explains how submarine cables function, examines their current status, and discusses their advantages and disadvantages. It also lays out practical procurement approaches.

Let’s dive deep to discover everything leaders need to know about submarine cables.

What Is The Undersea Cable Network?

The submarine cable network is a system of fiber-optic cables laid across the ocean floor. These cables transmit nearly all internet traffic, from multinational financial trades and enterprise cloud workloads to everyday social media interactions. They’re undeniably critical to IT infrastructure, forming the foundation of global connectivity.

The first subsea cables were built back in the 1850s to transmit telegraph messages. So, the tech this network leverages isn’t new. However, it’s now more advanced—and more vital—than ever before.

How A Submarine Cable Network Works From Shore To Shore

Let’s break it down in simple terms.

Basic Construction

Specialized manufacturers produce bundles of fiber-optic glass strands, each as thin as a human hair. Multiple protective layers of waterproof coatings or steel wire wrap these bundles. Professionals study the seafloor, plan the cable route, and lay cable on the ocean floor—burying it underneath the seabed in shallow waters.

Core Technology

Undersea cable bundles transmit data as pulses of laser light. Every pulse represents a piece of data, and the speed of light allows each flash to traverse the ocean in just milliseconds.

Repeaters

As light transfers across massive distances, its signal weakens. Small devices called repeaters, or signal boosters, are installed every 50-80 kilometers to strengthen the signal and ensure data reaches its destination.

Cable Landing Stations

Secure, nondescript buildings known as cable landing stations play a crucial role. They connect cables to terrestrial networks, transferring information from underwater lines to on-land systems.

Cable landing stations also perform surveillance and monitoring, power signal boosters, and house essential equipment.

Data Capacity

These networks possess immense data capacity, typically measured in terabits per second (Tbps).

Capacity varies significantly by cable.

Some older cables offer just 500 gigabits per second, while others present capacities in the hundreds of terabits per second. Global demand continues to expand, prompting providers to keep increasing subsea network capacity.

The Current State Of The Global Submarine Network

According to Telegeography, there are over 600 active and planned submarine cables as of early 2025. They form a sprawling high-speed information highway, quietly enabling most global online communication.

Telegeography estimates that the submarine cables in service span 1.48 million kilometers, underscoring the vastness of this underwater intercontinental web. This network serves a diverse range of organizations, including governments, telecommunications carriers, and content providers such as Google and Amazon.

The Pros And Cons Of Relying On Submarine Networks

Subsea communications networks are indispensable, and they present inarguably incredible benefits for interconnectivity. However, they also have a few notable downsides.

Pros

Submarine cables remain well ahead of their satellite counterparts in terms of bandwidth and consistency. These expansive fiber-optic networks offer unparalleled capacity and speed for transmitting large amounts of data across continents. For most critical applications, they provide superior efficiency and lower latency.

Submarine networks are also cost-effective due to the sheer volume of information transmitted. In short, undersea cables represent the gold standard for powering international data exchange on a large scale.

Cons

Subsea cable network repairs are incredibly complex, expensive, and time-consuming. And because cables are vulnerable to accidental physical damage from fishing trawlers, ship anchors, and natural disasters, repairs are often necessary.

They’re also susceptible to sabotage, as exemplified by a series of recent global incidents. For example, China built a new cable-cutting ship that can reach record depths, and Finland accused a Russia-linked vessel’s crew of damaging a Baltic Sea Cable.

Finally, the potential for data interception and surveillance engenders other geopolitical and information warfare risks. All of these realities urge organizations across the globe to enhance their security.

How Do Companies Procure Submarine Network Services?

Companies have several options for obtaining robust and reliable submarine cable network services.

Option #1: Building a Private Cable

This route requires significant upfront investments, extensive planning, and numerous regulatory approvals. It offers total ownership and complete control, but is an option for massive enterprises (or governments) with hundreds of millions to spend.

Option #2: Funding a New Cable With a Consortium

Joining a consortium—a group of companies that co-invest to construct a new undersea cable—is another approach. The consortium shares governance and ownership, and each buyer can use the portion of cable capacity they own independently.

This model is more accessible, offering companies expansive long-term capacity and a reasonable level of control with a lower financial burden. However, the requirement to coordinate decisions among consortium members can lead to conflicting priorities and reduced agility.

Option #3: Purchasing Bandwidth From a Carrier

Leasing capacity from a provider that already has cables is by far the most straightforward method for procuring these services. This approach comes in many forms, from pay-as-you-go capacity models to 20-year exclusive use agreements.

Regardless of the approach organizations take, they must overcome significant challenges when utilizing subsea cables to support their connectivity ecosystem. These barriers arise from procuring services, as well as effectively managing, monitoring, and integrating those services.

Due to these complex challenges and the deep industry expertise required to address them, many companies enlist the assistance of connectivity experts. Experienced partners simplify and optimize sourcing, implementation, and global connectivity management.

Advantage has been operating within this landscape for over 20 years, offering the skills and insights necessary for developing and implementing practical solutions. Think custom, flexible, and fully managed services that transform outcomes while simplifying processes.

Conclusion: Securing Your Global Connectivity From the Seafloor and Up

Submarine cable networks form the reliable backbone of worldwide business and intercontinental data exchange. However, they’re vulnerable to damage, sabotage, and other geopolitical risks.

As the strategic landscape of global connectivity continues to change, multi-location enterprises must be proactive in designing resilient, high-performance networks. To do so, they must consider the implications and vulnerabilities of undersea cable networks.

Advantage specializes in helping leaders navigate these obstacles. We’re here to assist with procuring subsea network services and building a secure, cost-effective, and future-proofed long-term strategy.

Are you confident in the resilience of your global network? Contact the experts at Advantage to start a conversation today.