Sagres: A Domestic Submarine Cable in Portugal
The Sagres submarine cable connects two points along the Portuguese coastline:
Burgau in the Algarve region and
Sesimbra near Lisbon. Spanning 302 kilometers, it is owned by Altice Portugal and has been in service since its recorded ready-for-service (RFS) year of 1998. While specific technical details such as design capacity, fiber pair count, and supplier are not publicly disclosed, the cable plays a role in domestic telecommunications within Portugal.
What makes Sagres interesting is its relatively short length and domestic focus, contrasting with many international submarine cables that span continents. Additionally, Sesimbra serves as a landing point for multiple other cables, creating redundancy and interconnection opportunities. However, public sources provide limited information about Sagres's operational specifics, leaving several technical and historical questions unanswered.
Quick facts
| Length | 302 km |
| Ready-for-Service (RFS) Year | 1998 (GeoCables database value; no conflicting sources surfaced) |
| Owner | Altice Portugal |
| Status | In service |
| Design Capacity | Not disclosed |
| Fiber Pairs | Not disclosed |
| Supplier | Not disclosed |
| Technology | Not disclosed |
| Landing Points | Burgau (Portugal), Sesimbra (Portugal) |
🗺 Show Sagres on the interactive cable map
Route
The Sagres cable connects Burgau and Sesimbra, two coastal towns in Portugal. Burgau is located in the southern Algarve region, known for its tourism and proximity to the Atlantic Ocean. Sesimbra, situated closer to Lisbon, is a key landing point for several submarine cables, including
BUGIO,
Equiano,
Europe India Gateway (EIG), and
SAT-3/WASC. This geographical positioning makes Sesimbra an important hub for both domestic and international connectivity.
The cable's route is entirely within Portuguese territorial waters, simplifying regulatory and maintenance considerations compared to international cables that cross multiple jurisdictions.
Why it was built and what it carries
Sagres was most likely built to enhance domestic telecommunications infrastructure within Portugal, providing a reliable connection between the southern and central regions of the country. While specific data about its traffic or capacity is not publicly disclosed, it likely supports a mix of voice, data, and internet services, catering to residential, commercial, and possibly governmental users.
Its role as a domestic cable contrasts with other cables landing at Sesimbra, which predominantly serve international routes. This distinction highlights Sagres's importance in ensuring localized connectivity within Portugal.
History: what can be established
The GeoCables database records Sagres's ready-for-service year as 1998, and no conflicting dates have been identified in industry sources. This places its construction during a period of rapid expansion in submarine cable networks globally, driven by increasing demand for digital communication.
Altice Portugal, the cable's owner, is a major telecommunications operator in the country, suggesting that Sagres was part of a broader strategy to modernize and expand Portugal's telecom infrastructure during the late 1990s.
Capacity and technology
Publicly available information does not disclose Sagres's design capacity, fiber pair count, supplier, or specific technology. Without operator documentation or industry sources, attributing these details would be speculative. Given its 1998 RFS date, it is reasonable to assume that the cable was initially equipped with technology suited to the telecom needs of that era, possibly upgraded over time to accommodate higher data rates.
Latency: the physics
Theoretical one-way light propagation over Sagres's 302-kilometer length is approximately 1.5 milliseconds, with a round-trip time (RTT) floor of 3.0 milliseconds. These calculations assume light traveling through fiber at speeds between 200,000 and 204,000 kilometers per second. However, real-world latency is higher due to additional factors such as land-based network tails, terminal equipment, and routing inefficiencies. No live measurements are currently available for this cable, so precise end-to-end latency figures cannot be confirmed.
Redundancy: what happens if it breaks
If Sagres were to experience an outage, redundancy would likely be provided by other domestic and international cables landing at Sesimbra, such as BUGIO, Equiano, Europe India Gateway (EIG), and SAT-3/WASC. These cables serve a mix of local and global routes, ensuring that connectivity between Portugal and other regions would not be entirely disrupted.
Repairing submarine cables typically involves deploying specialized cable ships equipped to locate, retrieve, and repair damaged segments. Given Sagres's relatively short length and domestic route, repair logistics would be simpler compared to international cables spanning thousands of kilometers.
Bottom line
- Sagres is a 302-kilometer domestic submarine cable connecting Burgau and Sesimbra in Portugal.
- Owned by Altice Portugal, it has been in service since 1998, according to GeoCables records.
- Specific technical details such as design capacity, fiber pairs, supplier, and technology are not publicly disclosed.
- Its theoretical round-trip latency floor is approximately 3.0 milliseconds, though real-world latency is higher.
- Redundancy is supported by other cables landing at Sesimbra, including BUGIO, Equiano, EIG, and SAT-3/WASC.