Why Subsea Cables Are a Specialty Line Behind the Data-Centre Build-Out
India's data-centre and AI build-out rests on a physical foundation that most of the conversation ignores: the submarine cables that carry the country's international internet traffic and the cable-landing stations where those cables come ashore. The great majority of international data moves through subsea cables, not satellites, and the hubs where India's systems land, principally around Mumbai on the west coast and Chennai on the east, are the choke points through which the data-centre clusters connect to the rest of the world. As the build-out adds hyperscale and AI capacity, demand for international bandwidth and for new cable systems landing in India is rising, and with it the insured value and the strategic importance of the cables and the landing stations.
Subsea cable systems are a specialty insurance line because they combine exposures from several conventional lines without sitting neatly in any of them. Laying a new cable is a marine construction project insured on a contractors-all-risks or marine construction basis. The cable in service, lying on or buried under the seabed across thousands of kilometres, faces a physical-damage exposure dominated by human marine activity rather than by the perils a land asset faces. The landing station ashore is a property and critical-infrastructure risk. And the service the system provides, connectivity, generates a business-interruption and liability exposure tied not to physical damage at the insured's own premises in the ordinary sense but to the loss of the system's function. An underwriter has to assemble cover across the marine, engineering, property and liability lines, because no single conventional policy answers the whole risk.
The parties involved are varied, which shapes who buys what. A cable system is typically owned by a consortium or a single operator, built by a specialist marine cable-laying contractor, and connected to data centres and networks by operators who depend on its capacity. The cable owner or consortium insures the system and the landing station; the cable-laying contractor insures the construction project; the data centres and connectivity-dependent businesses face the consequential exposure of an outage. The insurance programme spans these parties, and the broker placing it has to understand which exposures sit with whom.
This post works through the subsea cable risk as a specialty placement: the cable-laying contractors-all-risks and marine construction exposure, the in-service physical-damage exposure dominated by anchor drag and fishing activity, the repair-vessel availability and delay that drives the duration of any loss, the cable-landing-station property and critical-infrastructure exposure, and the non-damage business interruption and denial-of-connectivity exposure that is the hardest and most important part to cover.
Cable-Laying: Contractors-All-Risks and the Marine Construction Exposure
Building a new submarine cable system is a marine construction project with a distinctive risk profile, and it is insured on a contractors-all-risks or marine construction-all-risks basis, the offshore-marine cousin of the land-based CAR and erection-all-risks cover. The project runs from the manufacture and loading of the cable, through the survey of the route, the laying and burial of the cable along the seabed, the landing and termination ashore, to the testing and commissioning of the completed system, and each phase carries its own exposures.
The cable itself is a high-value manufactured product, and its loading onto the cable-laying vessel and its handling are early exposures. The laying operation is the core risk: the cable is paid out from the vessel and laid along a surveyed route, and in shallow water and near shore it is buried for protection. Damage during laying, a fault introduced into the cable, a problem during burial, damage from weather or sea state, or a loss involving the cable-laying vessel and its specialised equipment, can damage the cable and delay the project. The landing and shore-end works, bringing the cable through the surf zone and into the landing station, are a particular exposure because the near-shore environment is the most hazardous and the shore approach is technically demanding.
Delay in start-up and the consequential dimension
A cable project, like any large infrastructure project, carries a delay-in-start-up (DSU) or advance-loss-of-profits exposure: a physical loss during construction that delays the completion and commissioning of the system delays the revenue the system was to earn. For a cable serving the data-centre build-out, where capacity is contracted ahead and customers are waiting, the cost of delay can be significant, and the DSU cover, sitting alongside the construction-all-risks material damage, has to be sized to the realistic delay a serious construction loss would cause given the long lead time to mobilise a replacement cable and a cable-laying vessel.
The marine and liability dimensions of construction
The construction phase also carries marine liability and vessel exposures: the cable-laying vessel, the marine spread, the liabilities arising from the marine operation, and third-party exposures during the works. These engage the marine and liability lines alongside the construction cover, and the programme has to read them together so that an incident during laying, damage to the cable, a vessel issue and a third-party claim, does not fall into a gap between the construction, marine and liability sections. The broker building a cable-project programme has to align the marine construction-all-risks, the DSU, the marine hull and liability for the spread, and the third-party liability, and to set the handover from the construction cover to the operational cover at the point the system is commissioned and accepted.
In-Service Damage: Anchor Drag, Trawlers and Seabed Hazards
Once a cable is in service, lying on or buried under the seabed, its physical-damage exposure is unlike any land asset's, because the dominant cause of subsea cable damage worldwide is not a natural peril but human marine activity. Studies of global cable faults consistently find that the large majority of cable damage is caused by external aggression from shipping and fishing, principally anchor drag and fishing-trawler contact, with natural causes a smaller share. This shapes the entire in-service risk.
The single largest cause of cable faults is anchors: a ship that anchors over a cable, or whose anchor drags across the seabed, can hook and damage or sever the cable. The risk concentrates where shipping density is high and where vessels anchor, near ports, in anchorage areas and along busy approaches, which is precisely where landing stations and their cable approaches sit. Fishing, especially bottom trawling that drags gear along the seabed, is the other major cause, concentrated on the continental shelf where both cables and fishing activity are dense. The near-shore approaches to the Mumbai and Chennai landing hubs combine high shipping density, anchorage activity and fishing, so the shore-end of the cable, ironically the part that is buried for protection, sits in the most aggressive environment.
Natural and other hazards
Natural hazards are a smaller but real share: submarine landslides and turbidity currents (which can be triggered by earthquakes or by sediment-laden river outflows and can damage many cables at once), seabed abrasion and movement, and component failure of the cable or its repeaters over the long service life. The interaction of natural and human hazards matters: a single event such as a major turbidity current or a seismic event can damage multiple cables in a region simultaneously, which is an accumulation exposure for an insurer of several systems landing in the same area.
How the in-service damage cover works
The in-service physical damage to the cable is covered on a marine or specialist cable basis responding to the external-aggression and natural perils, and the underwriting turns on the route exposure: the shipping and fishing density along the route, the burial depth and protection in the high-risk near-shore and shelf zones, the route's exposure to anchorage areas and to natural hazards, and the cable's design and protection. The protection measures, deeper burial in high-risk zones, armoured cable in the near-shore, route selection away from anchorages and intense fishing, and charted cable-protection zones, are the primary risk controls, and a system that has invested in burial and protection along its exposed sections presents a lower fault frequency.
The counter-intuitive feature of subsea cable risk is that the most protected part of the cable, the buried near-shore section close to the landing station, sits in the most hazardous environment, because that is where shipping, anchoring and fishing are densest. The route exposure near the landing hubs, not in the deep ocean, drives much of the fault frequency, which is why burial depth, armouring and the charting of cable-protection zones in the approaches matter so much to the underwriting.
Repair-Vessel Availability and the Duration of a Loss
What makes a subsea cable fault expensive is not only the damage but the time and cost to fix it, and that is governed by the availability of a cable-repair vessel. A submarine cable cannot be repaired by sending a technician; a fault in deep water requires a specialised cable ship to locate the fault, grapple and recover the cable to the surface, cut out and replace the damaged section, splice it, test it and re-lay it on the seabed. There is a limited global fleet of these vessels, they operate on regional maintenance agreements covering many cables, and when a fault occurs the repair depends on a vessel becoming available, transiting to the site, and completing a weather-dependent operation at sea.
Why repair takes time
The repair timeline is driven by vessel availability, transit distance, weather and sea state, and the time the at-sea operation itself takes. A vessel under a regional maintenance agreement may be committed to another repair, may be far from the fault, and may be unable to work in poor weather. The result is that even a simple fault can take days to weeks to repair, and a complex fault or one occurring when vessels are scarce can take longer. For the operator, this means the system, or the affected segment, can be out of service for an extended period, and any business-interruption exposure runs for that whole period.
The insurance consequences of repair lead time
The long and variable repair time has direct insurance consequences. The material-damage cost of a repair, the vessel mobilisation, the at-sea operation and the replacement cable and components, is itself substantial because the repair resources are specialised and scarce. The business-interruption exposure, addressed in the connectivity section, runs for the repair duration, so the duration is the key driver of the BI loss size. And the underwriting of both depends on the repair arrangements the operator has in place: membership of a regional cable-maintenance agreement with assured access to a repair vessel, the location and coverage of the maintenance zone, and the spares and resources held. An operator with a firm maintenance agreement and assured vessel access faces a shorter and more predictable repair, and the underwriter should look for that arrangement as a primary control on the loss duration.
The Cable-Landing Station: Property and Critical-Infrastructure Risk
Where the subsea cable comes ashore it terminates in a cable-landing station (CLS), a secured building housing the terminating equipment, the power and the systems that bring the cable's capacity into the terrestrial network and onward to the data centres. The CLS is a property and critical-infrastructure risk, smaller in insured value than the cable system but concentrated and strategically critical, because it is the single point through which a cable's entire capacity passes ashore.
The CLS is a building packed with high-value, sensitive terminating and transmission equipment, dependent on reliable power and cooling, and exposed to the conventional property perils, fire, electrical fault, and at the coastal locations where landing stations sit, flood, storm surge and cyclone. The Mumbai and Chennai hubs are coastal and exposed to the cyclone and monsoon perils of their respective coasts, so the CLS property underwriting has to weigh the coastal natural-catastrophe exposure carefully, the flood and surge exposure of a coastal site, the wind exposure to cyclones, and the siting and protection of the critical equipment and power against these perils. The terminating equipment is high value and sensitive, so the fire protection, the power and cooling reliability, and the protection against water ingress are central.
Concentration and dependency
The CLS concentrates risk because a single station handles the shore end of one or more cables, and damage to or loss of function at the station can take a cable's capacity out of service even if the cable itself is intact. This concentration runs both ways: the cable depends on the station to deliver its capacity, and the station depends on the power, cooling and security that keep it running. A power failure, a cooling failure, a fire or a flood at the station is a single point of failure for the connectivity the station carries. The underwriting has to capture the station's resilience, the power redundancy and standby generation, the cooling redundancy, the flood and surge defences, the physical and cyber security, and the extent to which a single station is a single point of failure versus being backed by diverse routing.
Security and the regulatory dimension
A CLS is critical national infrastructure, and the regulatory and security dimensions matter. Landing of international cables and the operation of landing stations sit within the licensing and security framework for telecom infrastructure, and the physical and cyber security of the station, against intrusion, sabotage and cyber attack on the systems, is both a regulatory expectation and an insurance consideration. The property programme for the station should be read together with any cyber and liability cover, because an attack or a security failure at a CLS can combine property, business-interruption and liability dimensions.
Non-Damage Business Interruption and Denial of Connectivity
The hardest and most important part of subsea cable insurance is the business interruption and denial-of-connectivity exposure, because the loss that matters most, the loss of the connectivity the system provides, does not always follow physical damage at the insured's own premises in the way conventional BI requires, and it is felt by parties beyond the cable owner.
Conventional business interruption cover responds to a loss of revenue caused by physical damage to the insured's own property by an insured peril. A subsea cable BI can fit this where the cable owner loses capacity revenue because the cable is physically damaged. But the connectivity exposure is broader and more awkward. A cable fault that damages the cable far offshore interrupts the service; the financial loss is the lost capacity revenue for the owner and, more broadly, the cost to the data centres, networks and businesses that depend on the connectivity and now face degraded or lost international links. Much of the most significant loss is therefore a non-damage business interruption, an interruption of function and revenue that flows from a loss of connectivity rather than from damage to the claimant's own physical assets, and conventional property-triggered BI does not readily answer it.
The cable owner's BI
For the cable owner or consortium, the BI exposure is the loss of capacity revenue while a segment is out of service, and it can be covered as a business interruption following the physical damage to the cable, with the indemnity period sized to the realistic repair duration governed by repair-vessel availability. Because the repair time is long and variable, the indemnity period and the way the cover responds to a partial loss of capacity (a fault on one of several cables or fibre pairs) rather than a total outage need careful construction.
The dependent businesses and denial of connectivity
For the data centres, networks and connectivity-dependent businesses, the exposure is a denial of connectivity, the loss of the international links they rely on. Whether and how this is insurable is genuinely difficult: it is a non-damage interruption for them, it depends on a cable they do not own, and the standard answer in practice is resilience through diverse routing, multiple cables on diverse routes and diverse landing stations, so that no single cable fault denies connectivity. The insurance response, where it exists, has to be carefully defined around the trigger (what counts as a loss of connectivity), the sub-limits and the relationship to the diverse-routing resilience the business is expected to maintain. A business that relies on a single cable or a single landing station carries a denial-of-connectivity exposure that is hard to insure and better managed by route and station diversity.
The liability dimension rounds out the picture. A cable owner or operator may face claims from customers and counterparties for loss of service, and a cable-laying contractor faces liability exposures from the marine operation, so the liability line sits alongside the property, marine and BI cover. The programme across the whole system, the construction-all-risks and DSU during build, the in-service marine cable cover, the landing-station property, the business interruption and the liability, has to be assembled so the exposures fit together and the awkward connectivity loss is addressed as far as it can be.
For brokers placing subsea cable and landing-station programmes, the difficulty is exactly this assembly across specialty lines and the careful definition of triggers, especially for the non-damage connectivity exposure. Sarvada gives commercial insurance brokers structured, searchable access to insurer policy wordings so they can compare the marine construction, contractors-all-risks, marine cable, property and business-interruption grants, triggers, sub-limits and exclusions across the lines a cable programme spans, and define the connectivity and repair-duration terms precisely. Request Access to evaluate the platform for subsea cable, landing-station and critical-connectivity risks.
