Thetis Express: A Planned Submarine Cable Connecting Greece
The Thetis Express is a planned submarine cable system designed to connect key locations in Greece, including
Athens,
Heraklion, and
Milos. Owned by Vodafone, the cable is expected to play a significant role in enhancing connectivity within the region. With its ready-for-service (RFS) date recorded as 2027 in GeoCables' database, it is not yet operational and remains in the planning stage.
What makes Thetis Express particularly noteworthy is its focus on interconnecting Greek islands with the mainland, a corridor that is geographically significant but often underserved in terms of high-capacity submarine infrastructure. The cable’s exact design capacity, fiber pair count, and supplier details have not been disclosed publicly, leaving room for speculation about its technological specifications and performance capabilities.
Quick facts
| Name | Thetis Express |
| Length | 340 km |
| Ready-for-Service Year | 2027 |
| Owner | Vodafone |
| Status | Planned - Not yet in operation |
| Design Capacity | Not disclosed |
| Fiber Pairs | Not disclosed |
| Supplier | Not disclosed |
| Landing Points | Athens (Greece), Heraklion (Greece), Milos (Greece) |
🗺 Show Thetis Express on the interactive cable map
Route
The Thetis Express will connect Athens, the capital of Greece, to Heraklion, the largest city on the island of Crete, and Milos, a smaller island in the Cyclades group. This route is strategically important as it integrates key urban centers with island communities, potentially boosting economic and digital development in the region. Athens serves as a major hub for international and domestic telecommunications, while Heraklion and Milos represent critical nodes for regional connectivity.
Why it was built and what it carries
Thetis Express is being developed to address the growing demand for high-speed connectivity between mainland Greece and its islands. The cable will likely support broadband internet services, enterprise connectivity, and potentially mobile network backhaul for Vodafone’s operations in the region. While the design capacity remains undisclosed, the cable is expected to provide significant bandwidth to accommodate increasing data traffic and support the digital transformation of the Greek economy.
History: what can be established
The GeoCables database lists the ready-for-service year for Thetis Express as 2027. As of now, no industry sources have surfaced suggesting an alternative timeline, but delays in submarine cable projects are not uncommon due to factors such as permitting challenges, environmental considerations, and supply chain issues. Without further documentation from Vodafone or other stakeholders, the timeline remains speculative.
Capacity and technology
Publicly available information does not include details about the design capacity, fiber pair count, or technology employed in Thetis Express. Without operator documentation, it cannot be determined whether the cable will utilize advanced technologies such as space-division multiplexing (SDM) or the latest generation of optical amplifiers. These details will likely emerge closer to the cable’s deployment or once it becomes operational.
Latency: the physics
The computed one-way light propagation latency for the 340 km fiber segment is approximately 1.7 milliseconds. The theoretical round-trip time (RTT) floor is therefore around 3.3 milliseconds, assuming light travels at speeds between 200,000 and 204,000 km/s in fiber. Real-world latency will be higher due to additional factors such as land-based network equipment, routing, and processing delays.
Live latency measurements provided in the GeoCables database are unrelated to Thetis Express, as the cable is not yet operational. For example, the recorded minimum latency of 0.2 milliseconds for the Sydney-to-Sydney path is an artifact caused by rate-limited ICMP replies and does not represent actual physical latency. Careful analysis is required to interpret such data correctly.
Redundancy: what happens if it breaks
If Thetis Express were to experience an outage once operational, alternative cables landing in Athens, such as
EMC West-1,
MedNautilus Submarine System, and
Medusa Submarine Cable System, could provide redundancy for traffic to and from the Greek mainland. However, redundancy for connections to Heraklion and Milos may be more limited, depending on the availability of terrestrial or other submarine routes. Repairing submarine cables typically involves deploying specialized cable ships to locate and fix faults, a process that can take days or weeks depending on the severity of the damage and weather conditions.
Bottom line
- Thetis Express is a planned submarine cable owned by Vodafone, expected to be ready for service in 2027.
- It will connect Athens, Heraklion, and Milos in Greece, enhancing connectivity between the mainland and islands.
- Design capacity, fiber pair count, supplier, and technology details have not been disclosed publicly.
- The computed latency floor for the wet segment is approximately 3.3 ms round-trip, with real-world latency expected to be higher.
- Redundancy for mainland connections exists via other cables landing in Athens, but alternatives for island connections may be limited.