The subsea paradox: gray-zone threats, the "Subway Map" illusion, and the case for open subsea

 

From SubmarineNetworks by Winston Qiu

Cartography True digital openness requires physical visibility: Open Cables must no longer remain hidden beneath the waves

Submarine fiber-optic cables carry over 99% of intercontinental digital traffic, serving as the physical circulatory system of the global economy.
Yet, a fundamental contradiction lies at the heart of modern telecommunications: while the industry champions "Open Cable" architectures—characterized by open optical spectrum, disaggregated hardware, and carrier-neutral access—the physical geographic routes of these multi-billion-dollar assets remain veiled in obscurity, proprietary silos, or abstract cartography.

This transparency deficit creates a dangerous asymmetry.
Hostile state actors leveraging dual-use maritime survey vessels are actively conducting underwater reconnaissance on critical corridors like the Pacific Light Cable Network (PLCN).
Meanwhile, commercial ships, coastal states, and maritime security forces lack a single, standardized, open-access spatial map showing where these cables lie on the seabed.

To defend the world's digital backbone, the global community must align physical infrastructure policy with digital open-access principles: if a cable is open at the fiber level, its non-confidential physical route must be open on the global map.

An OPEN CABLE should never be a Hidden secret beneath the sea.

 

I. Tactical Flashpoint: Gray-Zone Reconnaissance over the PLCN

According to Maritime AI company Windward, a recent encounter in which a Chinese-flagged research vessel was filmed loitering directly over the Pacific Light Cable Network (PLCN)in the Philippine Sea illustrates the evolving "gray-zone" threat to seabed infrastructure.
Windward said the same ship had "operated repeatedly" in the Paracel Islands (西沙群岛), the Spratly Islands (南沙群岛), the Bay of Bengal and waters off Sri Lanka.
A subsequent report by the American magazine Newsweek brought widespread public attention to the incident, triggering follow-up coverage across major media outlets

Strategic Context of the PLCN

• High-Value Target: PLCN is an ~8,000-mile trans-Pacific fiber system linking Taiwan, the Philippines, and the United States, carrying vital financial, semiconductor supply chain, and government data.
• Geopolitical Backstory: Originally planned with a landing spur in Hong Kong, U.S. national security regulators blocked the Hong Kong segment in 2020 over data interception concerns.
• Operational since 2022 by removing the Hong Kong landing and fiber connection and routing directly into Taiwan and the Philippines, PLCN stands as a symbol of the Pacific digital geopolitical divide.

Operational Mechanics of the Encounter

• Dual-Use Hydrographic Reconnaissance: Nominally civilian research vessels equipped with multi-beam echo sounders, side-scan sonars, and sub-bottom profilers can map seabed contours, cable burial depths, and local bathymetry with high precision.
• Seabed Battlespace Preparation: Loitering at slow speeds over known cable paths allows operators to log precise coordinates for future cable-tapping, signal monitoring, or targeted severance during a crisis.
• Gray-Zone Probing: This activity forces coastal states like Taiwan and the Philippines to expend maritime assets monitoring, escorting, and warning off vessels, testing national rules of engagement without crossing the threshold of kinetic conflict.

Legal Analysis: Navigating UNCLOS, EEZ Jurisdictions, and the Debate Over Loitering vs. Transit

The legal classification of a foreign vessel operating near critical subsea infrastructure—or transiting strategic maritime chokepoints—lies at the intersection of conflicting interpretations of the United Nations Convention on the Law of the Sea (UNCLOS).
Determining whether an operational activity is legal or illegal depends heavily on the maritime zone, the nature of the operations, and whether a state is acting as a coastal state protecting its sovereign rights or a flag state exercising navigational freedoms.

The Competing Perspectives: Western Coastal Claims vs. Chinese Counter-Arguments

The Core Legal Friction: Continuous Transit vs. Stationary Loitering

At the center of this geopolitical debate is a fundamental disagreement over vessel conduct and speed within EEZs:

• The Speed and Purpose Argument: Coastal states argue that when a vessel reduces speed, alters course erratically, or holds a stationary position directly over a known subsea cable corridor, it loses the protection of "expeditious transit" and enters the realm of unauthorized survey or gray-zone interference.
• The Hydrographic & Military Survey Loophole: Flag states often exploit UNCLOS ambiguities, as the convention does not explicitly define the boundary between Marine Scientific Research (which requires coastal state consent in an EEZ) and military hydrographic surveying or intelligence gathering (which flag states claim is an unrestricted high-seas freedom).

Conclusion: Whether an encounter is viewed as a lawful exercise of high-seas navigation or an illegal infringement on coastal state jurisdiction depends on which legal doctrine a government applies.
While coastal nations view loitering over subsea fiber as an illegal, unauthorized survey targeting critical infrastructure, researching states defend such operations by citing navigational freedoms and pointing to similar military operations conducted by Western allies across regional EEZs.

II. The Multi-Layered Defense: How to Protect Seabed Arteries

Defending subsea fiber against physical sabotage or intelligence probing requires a integrated defense matrix combining commercial sensing technology with state sovereign enforcement.

1. What Cable Owners & Consortiums Must Do

a) Deploy Distributed Acoustic Sensing (DAS): Optoelectronic interrogators turn active or dark fiber within the cable into continuous, long-range acoustic sensors. DAS can detect nearby vessel engine signatures, dropped anchors, bottom trawling, or underwater submersibles in real time.

b) Geofenced AIS Integration: Automated systems merge vessel Automatic Identification System (AIS) data with network operations centers (NOCs), triggering immediate security alerts when a vessel slows down or loiters inside a cable corridor.

c) Physical Hardening & Mesh Redundancy: Deep-burying cables 2–3 meters into the seabed where feasible and routing bandwidth across redundant, geographically diverse paths so that a single severed trunk does not cut off national connectivity.

2. What Coastal States Must Do

a) Establish Statutory Cable Protection Zones (CPZs): Enact laws declaring CPZs around critical cable routes, making bottom-trawling, commercial dredging, dropping anchor, or unauthorized loitering explicitly illegal

b) Strategic Transparency ("Naming and Shaming"): Publicly release Coast Guard video, AIS tracking logs, and spatial data when foreign research or commercial ships loiter over cables. Exposing gray-zone operations imposes diplomatic and political costs on foreign aggressors.

c) Public-Private Intel Fusion Centers: Establish direct data pipelines between private Cable Landing Stations (CLS) and naval/coast guard command centers to allow rapid dispatch of patrol ships or aerial drones when an anomaly is detected.

3. Operational Case Study: How Taiwan and the Philippines Responded to the PLCN Incident

The recent loitering of a Chinese-flagged research vessel directly over the Pacific Light Cable Network (PLCN) provided a live operational test of how regional coastal states respond to subsea gray-zone threats.

The vessel's tracked path traversed three distinct maritime legal zones: Taiwan's EEZ, the Philippines' EEZ, and the High Seas.
Both Taiwan and the Philippines deployed a combination of active maritime enforcement, strategic transparency, and regulatory domain awareness to counter the activity.

Key Takeaway: The joint response highlights that while regional coast guards lack the legal authority to seize foreign ships in international waters or EEZs without evidence of physical damage, real-time physical interception combined with public media exposure remains the most effective immediate countermeasure against subsea gray-zone probing.

III. The Cartographic Illusion: Schematic "Subway Maps" vs. Spatial Reality

A major vulnerability in subsea infrastructure security stems from a widespread public and policy misconception: the belief that accessible global maps of subsea cables already exist.

The "Subway Map" Fallacy

Platforms like TeleGeography's Submarine Cable Map and Infrapedia are widely used, highly valuable commercial tools.
However, they are not geographical maps.
They are stylized, schematic diagrams—functionally identical to a metro system map.

• They display logical connectivity (Point A connects to Point B).
• They do not reflect true geographic coordinates, bathymetric alignments, or actual physical trajectories across territorial seas, Exclusive Economic Zones (EEZs), or the High Seas.

The Missing Public Spatial Layer

To navigate, anchor, or protect infrastructure safely, mariners and security forces require Route Position Lists (RPLs)—centimeter-accurate geographic datasets.
Today, actual RPL spatial data is fragmented into three locked domains:

• Proprietary Commercial Vaults: Held privately by cable owners, survey firms, and installers who treat detailed bathymetric paths as trade secrets.
• Paid Electronic Navigational Charts (ENCs): Encoded into official marine navigation databases (managed by national hydrographic offices like UKHO or NOAA) accessible primarily through expensive shipboard ECDIS equipment.
• Siloed Regulatory Filings: Buried inside static PDF attachments in environmental or regulatory applications (e.g., U.S. FCC filings).

IV. The ICPC Vision vs. Spatial Silos

The International Cable Protection Committee (ICPC) and the International Hydrographic Organization (IHO) have long advocated for integrating subsea cables into standard nautical charting (under IHO Resolution 4/1967).
The goal was straightforward: mariners cannot avoid hazards they cannot see.

While the ICPC framework successfully pushed for cable lines on official nautical charts, this data remains locked inside closed maritime navigational software.
There is no open-access, global, GIS-compatible spatial layer showing the world's physical digital arteries.

“The ICPC recommends that governments and industry continue to identify submarine cables on nautical charts in a timely and accurate manner in order to ensure maritime safety and protection of global critical infrastructure.”International Cable Protection Committee (ICPC) 

V. The "Open Cable" Paradox & Call to Action

Over the past decade, the telecommunications industry underwent a revolution driven by the Open Cable architecture model.
Hyperscalers and consortia dismantled proprietary vendor lock-in, embracing open optical spectrum, carrier-neutral landing stations, and interoperable wet-plant interfaces.

Yet, this openness stops at the shoreline.
The physical paths of these cables remain hidden behind commercial secrecy, regulatory silos, or abstract web vector graphics.

 

Why Hiding Physical Routes No Longer Works

The legacy justification for keeping cable paths secret was security through obscurity.
However, this logic has collapsed:

• Hostile state actors already possess the technology to find them. Advanced sonar, satellite RF tracking, and oceanographic research ships easily map cables regardless of whether the RPL is public.
• Commercial ships break them by accident. Fishermen and merchant captains drag anchors and nets through cables precisely because accurate, real-time spatial representations are not integrated into basic, accessible charting tools.
• Security forces are blind. Coast Guards and allied navies attempting to monitor gray-zone loitering lack an integrated, open GIS overlay combining live AIS vessel tracks with physical cable lines.

Conclusion: A Global Call for Open Seabed Mapping

You cannot build a resilient, open digital global society on hidden physical roads.
The world maps its physical roads, highways, and bridge infrastructure openly to ensure public safety, urban planning, and defense.
Subsea fiber-optic cables—the highways of global civilization—require the same spatial transparency.

A landmark step in international coordination was the creation of the International Advisory Body for Submarine Cable Resilience (ITU IAB), established by the International Telecommunication Union (ITU) in partnership with the International Cable Protection Committee (ICPC).
Bringing together governments, regulatory authorities, telecom operators, and maritime experts, the ITU IAB operates through specialized Working Groups targeting deployment, repair logistics, risk mitigation, and route diversity.
However, standardized, open seabed cartography remains the critical missing link in global infrastructure security.

Strategic Roadmap: Integrating Open Mapping into the ITU IAB Action Plan

1. Adopt Open Seabed Mapping as an ITU IAB Core Action Item: The ITU IAB should formally incorporate open subsea cartography into its global resilience agenda—specifically within Working Group 2 (Risk Identification, Monitoring and Mitigation). By establishing a UN-backed open GIS framework, the ITU IAB can lead the shift from closed navigational silos to transparent global spatial awareness.
2. Fulfill the ICPC Vision via a UN-Backed Open Global Cable Registry: The ITU, International Maritime Organization (IMO), International Hydrographic Organization (IHO), and ICPC should collaborate under the ITU IAB banner to build a standardized, open-access global GIS layer for all commercial subsea cables across Territorial Seas, EEZs, and the High Seas.
3. Declassify Non-Sensitive Geographic RPLs: National regulatory bodies (such as the U.S. FCC, European BEREC, and regional telecom authorities) should mandate that non-confidential physical Route Position Lists (RPLs) be published in standard, open GIS formats (GeoJSON/KML) as a condition for granting subsea landing licenses.
4. Unify Open Spectrum with Open Geography: The telecommunications industry must broaden its definition of "Open Cable." True digital resilience requires pairing open optical spectrum and disaggregated hardware with open cartographic visibility on the global map.

By taking up open seabed cartography as a primary mandate, the ITU Advisory Body and global stakeholders can eliminate gray-zone ambiguities, empower maritime security forces, and protect the physical circulatory system of the global internet.

“True digital openness requires physical visibility: Open Cables must no longer remain hidden beneath the waves.”