Pencan-9

PENCAN-9: A Hidden Backbone Between Mainland Spain and the Canary Islands

PENCAN-9 is one of the submarine fiber-optic cables in Telefónica's PENCAN network, designed to connect the Iberian Peninsula with the Canary Islands. It is not an international transatlantic cable in the conventional sense but rather a domestic Spanish backbone: it carries internet traffic, telephone communications, corporate data, and government system traffic between the Canary Islands and mainland Spain.

However, PENCAN-9 is surrounded by a notable issue: there is an extreme scarcity of primary technical information in open sources, and some catalogs even conflict on its launch date and landing points. Therefore, it is important to distinguish verified facts from assumptions and automatically replicated data.

Key Specifications

🗺 Show Pencan-9 on the interactive cable map

The length of 1,398 km, Telefónica's ownership, the Chipiona-Tarahales route, and the system's operational status are cited in several contemporary cable catalogs.

Where PENCAN-9 Runs

According to modern cartographic databases, the mainland landing point of PENCAN-9 is located in Chipiona, in the province of Cádiz, at approximately 36.7313° N, 6.4289° W. The Canary Islands landing point is identified as Tarahales, in the Las Palmas de Gran Canaria area, with coordinates around 28.0964° N, 15.4507° W. The total cable route length is estimated at 1,398 km.

Tarahales is not a separate island or an international hub; it is a district on the island of Gran Canaria connected to the urban infrastructure of Las Palmas. After reaching the cable station, traffic can be distributed through Telefónica's terrestrial networks and inter-island cables to Tenerife, Fuerteventura, Lanzarote, La Palma, La Gomera, and El Hierro. The Canary Islands inter-island network includes PENCAN-5, TRANSCAN, CANDALTA, TELAPA, TEGOPA, and other systems, most of which form rings or partially redundant routes.

Thus, while PENCAN-9 physically lands on Gran Canaria, its effective service area is much broader: through the backbone and inter-island network, its capacity can be utilized by subscribers and organizations across the entire archipelago.

Purpose of the PENCAN Network

The Canary Islands are located more than a thousand kilometers from continental Europe. Building a conventional terrestrial optical line to Spain's core network is impossible for them. Satellite communication can provide backup or access in remote locations, but it has historically lagged behind submarine fiber in terms of capacity, latency, and the cost of transmitting large volumes of data.

For this reason, Telefónica has consistently developed the PENCAN - Península-Canarias - network. In 2015, the company described this network as comprising four geographically separated fiber-optic cables: PENCAN-6, PENCAN-7, PENCAN-8, and PENCAN-9. Their collective goal is to ensure high availability and the ability to reroute traffic in case of damage to one of the lines.

The network was not built for a single specific service. Through these channels, the following are transmitted:

• home and mobile internet;
• voice communications;
• operator backbone traffic;
• access to data centers and cloud platforms;
• corporate VPNs and dedicated channels;
• government data;
• banking transactions and payment traffic;
• video, streaming services, and CDNs;
• scientific data;
• systems serving the tourism industry.

Telefónica directly links the development of the Canary Islands' submarine lines to the needs of residents, businesses, government institutions, approximately 16 million tourists annually, the TEIDE HPC and LAPALMA HPC supercomputers, and the Canary Islands Institute of Astrophysics.

Construction History: What Has Been Established

Network Formation

PENCAN-9 is not an isolated project but part of a multi-generational network. By the early 2000s, Telefónica was already operating PENCAN-6, and in subsequent years, PENCAN-7, PENCAN-8, and PENCAN-9 were introduced. One industry review dates the launch of PENCAN-9 to 2011, alongside PENCAN-7 and PENCAN-8.

However, according to GeoCables' sources, the Ready for Service date for PENCAN-9 is listed as 2016.

This discrepancy cannot be resolved definitively without Telefónica's project documentation. Possible explanations include:

1. 2011 may refer to the initial construction or an earlier configuration of the system.
2. 2016 might indicate the deployment of an upgraded optical platform.
3. Industry databases may have recorded an incorrect or generalized date.
4. The name PENCAN-9 might have been applied to the route or assets after reconfiguring existing infrastructure.

Therefore, the statement "PENCAN-9 was built in 2016" appears too definitive. It is more accurate to say that the system existed as part of the PENCAN network no later than August 2015, and several modern catalogs list 2016 as the date it became ready for commercial operation. The existence of PENCAN-9 in August 2015 is confirmed by a press release about the modernization of PENCAN-7 and PENCAN-8, where PENCAN-9 is already mentioned as one of the four operational cables in the network.

Construction Process

No public data has been found regarding the cable-laying vessel, the manufacturer of PENCAN-9 itself, the number of repeaters, the type of fiber, the depth of installation, or the exact configuration of the shore sections. Therefore, attributing the project to a specific vessel or manufacturer without Telefónica's documentation would be speculative.

From an engineering perspective, constructing such a route typically involves:

1. Hydrographic surveying from Cádiz to Gran Canaria.
2. Selecting a route that avoids steep slopes, unstable seabed areas, and regions of heavy maritime traffic.
3. Manufacturing deep-sea and armored coastal cables.
4. Installing optical repeaters at calculated intervals.
5. Laying the cable from a cable-laying vessel.
6. Burying the cable in shallow waters where the risk from anchors and fishing gear is highest.
7. Bringing the shore ends to cable stations.
8. Installing terminal equipment and integrating the route into Telefónica's transport network.
9. Conducting optical and load testing before commercial activation.

For a route nearly 1,400 km long, a passive, repeaterless design is highly unlikely. Such a route typically requires submarine optical amplifiers and a power feed system from the shore stations.

Capacity and Modernization

It is known that in 2015, Alcatel-Lucent Submarine Networks and Telefónica upgraded the neighboring PENCAN-7 and PENCAN-8 by deploying 100 Gbps optical channel technology. This upgrade reportedly increased available capacity more than tenfold and enabled further scaling to multi-terabit levels.

However, this does not automatically imply that PENCAN-9 received the same platform. The press release specifically mentions PENCAN-7 and PENCAN-8 as being upgraded; PENCAN-9 is referenced only as part of the overall network.

Latency Estimates

For a cable 1,398 km long, the lower physical limit of latency can be estimated.

The speed of signal propagation in optical fiber is approximately 200,000-204,000 km/s. Therefore:

• minimum one-way propagation latency: approximately 6.9 ms;
• minimum physical RTT for the submarine segment: approximately 13.7-14.0 ms.

This only accounts for the time it takes light to travel through the fiber. In a real network, additional latency is introduced by the terrestrial route, terminal equipment, routers, transponders, queues, and the path to the measurement node. As a result, the practical RTT between a user in Gran Canaria and a node in southern Spain could be higher - roughly in the range of 18-30 ms, depending on the destination and the actual IP route.

GeoCables displays ICMP measurements associated with the PENCAN-9 page, but values from remote probes cannot be considered a measurement of the cable's latency: they reflect the full internet route from the probe to the selected target, not the submarine segment alone.

Who PENCAN-9 Serves

It cannot be stated that the cable is tied to a specific list of operators or particular clients: commercial agreements and capacity allocations are not publicly disclosed.

At the infrastructure level, it primarily serves Telefónica's transport network. Indirectly, its capacity may be used by:

• Movistar customers;
• Telefónica's mobile network;
• corporate clients;
• government agencies;
• other operators purchasing transport or mutual redundancy;
• cloud and content services whose traffic passes through Telefónica's network.

Geographically, the primary service area is Gran Canaria and, through the inter-island network, the entire Canary Islands archipelago. The population of the Canary Islands is approximately 2.26-2.27 million people, with the majority concentrated on Gran Canaria and Tenerife.

How Critical is PENCAN-9?

Critical as Part of the System, but Not a Single Point of Failure

PENCAN-9 should be considered a critically important backbone asset, but not the sole communication line for the Canary Islands. The archipelago is connected to the outside world by several systems operated by Telefónica and independent operators, including PENCAN-7/former SAT-3 segment, PENCAN-8, Canalink, WACS, ACE, and 2Africa.

In the event of a single failure of PENCAN-9, it is unlikely that the Canary Islands would lose internet connectivity entirely. Traffic would likely be rerouted through other paths. The impact would depend on:

• the current load on neighboring cables;
• available backup capacity;
• the location of the damage;
• the ability to automatically reroute traffic;
• Telefónica's agreements with other infrastructure owners.

Potential consequences include increased latency, overloading of backup lines, reduced available bandwidth, and degradation of some corporate services. Complete isolation of the archipelago would require simultaneous damage to multiple geographically separated routes.

Why the Risk Remains Significant

The distance to the mainland is approximately 1,400-1,500 km, so repairs require a specialized vessel, locating the damage, retrieving the cable from the seabed, installing a new section, and retesting. Depending on weather conditions, depth, and vessel availability, restoration could take days or weeks.

Additionally, a significant portion of the PENCAN infrastructure already belongs to an older generation. Telefónica has announced the construction of PENCAN-X, which is intended to replace one of the three existing routes nearing the end of its service life. The company has not specified in its press release which cable is being replaced, so it cannot be stated that it is PENCAN-9.

The Future: PENCAN-X

The PENCAN-X project began in December 2024 and is expected to take approximately 24 months. The new route is planned to connect the province of Cádiz with Gran Canaria, featuring eight fiber pairs and independently providing roughly ten times the capacity of all existing infrastructure on this route. Dedicated optical spectrum and automatic channel restoration have also been announced.

This context is crucial for evaluating PENCAN-9. Even if it remains operational, its role will likely change: from being a primary working backbone to serving as a backup or supplementary route. If it is the cable selected for decommissioning, PENCAN-X will effectively become its successor. However, there is no official confirmation yet as to which specific older cable will be replaced.

Final Assessment

PENCAN-9 is a regionally critical cable of national importance. Its purpose is not to connect continents but to ensure the digital integrity of Spain's territory located in the Atlantic Ocean.

Key facts:

• length - approximately 1,398 km;
• operator - Telefónica;
• route in modern databases - Chipiona-Tarahales/Gran Canaria;
• service area - Canary Islands via mainland and inter-island networks;
• physical minimum RTT for the submarine segment - approximately 14 ms;
• exact capacity and number of fiber pairs are not publicly disclosed;
• a single break will not isolate the entire archipelago but will reduce redundancy and may cause congestion;
• the cable is vital for residents, tourism, businesses, government services, and research centers;
• its long-term role depends on the deployment of PENCAN-X.