Trans-Caspian Cable Goes Live at 400 Tbps

A 380-kilometre submarine cable now carries up to 400 Tbps of traffic across the Caspian Sea, linking the telecoms infrastructures of Kazakhtelecom and AzerTelecom between Aktau in Kazakhstan and Sumgait in Azerbaijan. Officials launched the system on Thursday, capping a construction effort that began only in August.

The Trans-Caspian Submarine Cable System is the first product of CaspiLink, a joint venture the two operators set up in 2024 specifically to build the link. They hired Pioneer Consulting, a subsea cable project management firm, in April 2025 to oversee construction. The desktop study and marine route survey were completed last year.

Why does a single cable matter to Europe-Asia traffic?

The route gives operators a choice. Traffic can now move from Kazakhstan through Azerbaijan, Georgia and Turkey toward Europe, in addition to or instead of the existing terrestrial routes that run through Russia. For a landlocked country whose international data transit has depended heavily on Russian infrastructure, that alternative changes the commercial and political arithmetic of connectivity.

The commercial framing from the operators is expansive. Emil Masimov, chairman of the board of AzerTelecom, called the project of strategic importance in expanding the region's international digital transit capacity, strengthening connectivity along the Middle Corridor, and diversifying data transmission routes between Europe and Asia.

His Kazakh counterpart went further. Bagdat Musin, chairman of the board of Kazakhtelecom, said: "More than a subsea cable connecting Azerbaijan and Kazakhstan, it represents a new digital route that will expand data transmission between Asia and Europe." He added that the project will strengthen international digital connectivity, enhance the resilience of telecommunications infrastructure, and create new opportunities for the digital development of both countries and the wider region.

What is the political and regulatory context?

The cable sits at the intersection of two large initiatives. Kazakhstan's president, Kassym-Jomart Tokayev, described it in a separate statement as a digital counterpart to the Trans-Caspian International Transport Route (TITR), known as the Middle Corridor, which creates a trade path from Southeast Asia and China to Europe via Kazakhstan, the Caspian Sea, Azerbaijan, Georgia and Turkey.

Kazakhstan has also positioned the cable within the "Digital Silk Road" project that Beijing leads as an offshoot of its Belt and Road Initiative. Kazakhstan is a BRI signatory, so the subsea link serves both Chinese connectivity ambitions and Central Asian efforts to diversify transit routes.

Tokayev added a domestic economic argument. He said the cable will play a key role in attracting global technology companies and in developing cloud services and AI infrastructure in Kazakhstan.

Whether the 400 Tbps of capacity attracts hyperscalers and AI workloads remains to be demonstrated; for now, that claim sits in the category of presidential aspiration rather than contracted demand.

What comes next?

A second phase is already planned. It would extend the system from Sumgait to Turkmenbashi in Turkmenistan, adding a third Caspian littoral state to the network. No timeline has been given for that segment, so the pace of expansion will depend on how quickly the first phase fills with traffic and on Turkmenistan's willingness to join the venture.

For now, the operators have a working cable, a 400 Tbps design capacity, and a route that no longer requires Kazakh data to cross Russian soil on its way west.