In the Spanish digital ecosystem, major data centers, the hybrid cloud, and 5G deployment often make the headlines. However, there is less visible infrastructure that ensures all of this functions equally well in the overseas territories: undersea cables.
The CNMC (National Commission on Markets and Competition) has just published a key report on the competitive status and connectivity of Canary Islands, Balearic Islands, Ceuta, and Melilla. Its overall conclusion is positive: telecom services in these regions are comparable to those on the mainland thanks to a “reasonably good” network of undersea cables. However, the regulator warns of upcoming challenges: insufficient redundancy on some routes, aging cables, and the need to strengthen network resilience in an era where the cloud permeates everything.
The foundation of the cloud: submarine data transport
7.5% of the Spanish population — roughly 3.6 million people — live outside the mainland. For these regions, terrestrial fiber optics are not enough: their access to the Internet, cloud applications, and critical services depends on cables that traverse the seafloor to thousands of meters below the surface.
Without them, reliable access to SaaS platforms, public and private clouds, video conferencing, IoT, and e-government services would be unthinkable. In practice, every connection to Microsoft Azure, AWS, Google Cloud, or a data center in Madrid or Barcelona relies on these links as a transportation backbone.
A growing ecosystem of 15 cables
Currently, there are 15 operational undersea cables connecting the Balearic Islands, Canary Islands, Ceuta, and Melilla to the mainland, with three more under construction for operation in the next two years.
- Balearic Islands have 4 cables, some with fiber exchange agreements that allow real redundancy between Telefónica, Islalink, and Red Eléctrica.
- Canary Islands feature 5 cables, though the distances (1,500 km to Cádiz) make their network more vulnerable. In 2026, the Pencan 10 will add to the network, with an investment of €37.3 million (€10.5 million co-funded by the EU). The second cable for El Hierro is also underway, a strategic move to eliminate the risk of a single-link dependency for the island.
- Ceuta has 4 active cables and will add 2 more in 2026. Meanwhile, Melilla relies on 2 cables, one of which has a regulatory obligation to share 30% of its capacity with other operators to promote competition.
Redundancy, resilience, and digital sovereignty
In cloud terms, the issue is not only capacity but resilience. A failure in a cable can cause interruptions in access to critical public and private cloud services, from SAP to cybersecurity solutions or remote backups.
Therefore, the CNMC emphasizes three priorities:
- Physical redundancy: multiple cables along the same route or alternative routes.
- Fiber exchange agreements: operators sharing capacity to mitigate the risk of outages.
- Technological renewal: some cables date back to the late 1980s and need replacement planning before reaching their operational limits.
This reinforcement is even more crucial as Spain aims to position itself as a hub for data centers and sovereign clouds in Europe, with new hyperscale campuses in Madrid, Barcelona, and the Canary Islands.
Ceuta and Melilla: success stories in bandwidth
The report highlights Ceuta and Melilla as exemplary cases: both cities have near-complete coverage of ultra-fast broadband, with metrics above the Spanish average and well above European standards.
This benefits not only local households and businesses but also makes these cities strategic points for cloud services along the southern Mediterranean coast, capable of serving as low-latency nodes towards North Africa.
Canary Islands and the challenge of geographic isolation
The Canary archipelago remains the biggest challenge. Despite multiple active cables, the distance to the mainland requires constant investments in capacity and resilience. Additionally, the CNMC notes that El Hierro still relies on a single link, posing an unacceptable risk for a territory aiming to attract technology investment and edge computing projects.
The deployment of Pencan 10 in 2026 and the new canal link to El Hierro are critical pieces to ensure Canary Islands can fully integrate into the national and European cloud strategy.
More than just telecommunications: critical infrastructure for the digital economy
Submarine connectivity is not a minor telecom issue. It is a critical infrastructure for the digital economy and cloud business:
- Companies: depend on these links to access ERP, CRM, and AI cloud services.
- Governments: need stable connectivity for e-government and defense.
- Data centers: require redundancy to ensure high availability in hosting, virtualization, and disaster recovery services.
- Users: from streaming to telecommuting, all rely on these cables.
Conclusion: the cloud also relies on the seabed
The CNMC report confirms that the current connectivity of the Balearic Islands, Canary Islands, Ceuta, and Melilla is solid and comparable to the mainland, but also emphasizes that resilience is a work in progress. The introduction of new cables in 2026 and the renewal of aging assets will be key to safeguarding access to the cloud, data centers, and edge computing in regions strategic for Spain.
For the digital economy, the message is clear: without undersea cables, the cloud cannot exist.
Frequently Asked Questions (FAQ)
How many undersea cables connect the overseas territories to the mainland?
Currently, there are 15 operational cables and 3 more under deployment to be operational before 2027.
Why are submarine cables critical for the cloud?
Because all traffic toward platforms like AWS, Azure, Google Cloud, or national data centers depends on these links as the backbone of transport.
What are the risks if a territory depends on a single cable?
A physical failure can cut off entire islands or autonomous cities, affecting essential services like banking, digital health, or public administration.
What investments are planned to enhance connectivity?
Highlights include the Pencan 10 in the Canary Islands (2026), the second cable for El Hierro (2026), and two new cables for Ceuta (2025/2026), all aimed at improving capacity and redundancy.
Source: Submarine Cables in Spain (telefonos.es)