Adria-1

Adria-1: A regional submarine cable linking Greece, Croatia, and Albania

Adria-1 is a submarine telecommunications cable that spans approximately 440 kilometers, connecting three landing points: Corfu in Greece, Dubrovnik in Croatia, and Durres in Albania. Operational since 1996, according to GeoCables data, it is owned jointly by ALBtelecom and Hrvatski Telekom. The cable serves as a regional link within the Adriatic Sea, facilitating communication and data transfer between these countries. What stands out about Adria-1 is the limited publicly available information regarding its technical specifications, such as design capacity, fiber count, and supplier details. Additionally, live latency measurements from remote probes reveal significant differences between theoretical propagation times and real-world internet performance, offering insight into the broader network dynamics and infrastructure challenges.

Quick facts

Name	Adria-1
Length	440 km
Ready for service	1996 (GeoCables database)
Owners	ALBtelecom, Hrvatski Telekom
Status	In service
Design capacity	Not disclosed
Fiber pairs	Not disclosed
Supplier	Not disclosed
Technology	Not disclosed
Landing points	Corfu (Greece), Dubrovnik (Croatia), Durres (Albania)

🗺 Show Adria-1 on the interactive cable map

Route

Adria-1 connects three strategic locations along the Adriatic Sea. Its southernmost landing point is Corfu, a Greek island known for its historical significance and proximity to Albania. The cable crosses the Adriatic to land in Durres, Albania's primary port city and an important economic hub. Finally, it reaches Dubrovnik, Croatia, a UNESCO World Heritage site and a growing regional center for telecommunications. This corridor provides connectivity between southeastern Europe and the Mediterranean.

Why it was built and what it carries

Adria-1 was likely built to enhance regional connectivity in southeastern Europe, where terrestrial infrastructure faces challenges due to mountainous terrain and geopolitical considerations. By linking Greece, Albania, and Croatia, the cable facilitates international telecommunications, including voice, data, and internet services. Its role may also include supporting cross-border business, tourism, and government communications. However, specific details about the cable's traffic volumes and utilization rates are not publicly disclosed.

History: what can be established

GeoCables records Adria-1's ready-for-service year as 1996, but no alternative dates have been surfaced from industry sources to challenge this. The cable's ownership by ALBtelecom and Hrvatski Telekom suggests it was developed as a cooperative effort to meet regional connectivity needs. Its continued operation as of 2023 indicates that it has been maintained and upgraded sufficiently to remain viable, though details about its maintenance history or any major repairs are not publicly available.

Capacity and technology

Publicly available information does not disclose Adria-1's design capacity, fiber pairs, or supplier. Without operator documentation, it cannot be stated whether the cable has been upgraded to support modern high-capacity technologies such as wavelength-division multiplexing (WDM). Given its age, it is plausible that the cable has undergone retrofits to remain competitive, but attributing specific technological advancements without evidence would be speculative.

Latency: the physics

Theoretically, light traveling one way through Adria-1's 440 km fiber would take approximately 2.2 milliseconds, with a round-trip time (RTT) floor of 4.3 milliseconds. However, live latency measurements from remote probes show significantly higher values:

• Corfu to Dubrovnik: minimum 14.6 ms, average 57.2 ms
• Dubrovnik to Corfu: minimum 41.1 ms, average 87.4 ms
• Odessa to Dubrovnik: minimum 54.2 ms, average 63.3 ms
• Sydney to Dubrovnik: minimum 240.8 ms, average 242.0 ms
These discrepancies arise from additional factors such as land-based network tails, routing inefficiencies, and terminal equipment delays. The data underscores the difference between theoretical cable latency and real-world internet performance.

Redundancy: what happens if it breaks

In the event of a failure, redundancy for Adria-1's corridor is partially provided by the Italy-Albania cable, which also lands at Durres. This alternative route could mitigate disruptions to Albania's connectivity but would not cover the full geographic scope of Adria-1. Repair logistics for submarine cables typically involve deploying specialized cable ships to locate, retrieve, and repair the damaged segment, a process that can take weeks depending on the fault's severity and location.

Bottom line

• Adria-1 is a 440 km submarine cable connecting Corfu, Dubrovnik, and Durres.
• Operational since 1996, owned by ALBtelecom and Hrvatski Telekom.
• Technical specifications such as design capacity and fiber pairs are not publicly disclosed.
• Live latency measurements reveal significant differences from theoretical propagation times.
• Redundancy is partially provided by the Italy-Albania cable.