NTT announced Tuesday the launch of a new joint venture, Seren Juno Network Co., Ltd. (“Seren”) which has been founded to construct and operate “JUNO”, the new and largest trans-Pacific submarine cable system. The JUNO cable system will provide a system capacity of 350Tbps over 20 fiber pairs.

The shareholders of Seren comprising NTT Ltd. Japan Corporation, Mitsui & Co., Ltd., PC Landing Corp, and JA Mitsui Leasing, Ltd

Among the shareholders, Mitsui & Co., Ltd.(三井物産株式会社), is one of the largest general trading companies in Japan, being a subsidiary of Mitsui Group, one of the largest keiretsu in Japan and one of the largest corporate groups in the world. JA Mitsui Leasing, Ltd. is a specialty finance firm that focuses on leasing, installment sales, financing, and other associated businesses, established in 2008 with Mitsui & Co., Ltd. as one of its major shareholders. PC Landing Corp, a US company, is wholly owned by NTT America, Inc. which is a wholly owned subsidiary of NTT Ltd.. PC Landing Corp holds submarine cable landing licenses in the US and Japan for the PC-1 cable system, owns and operates PC-1 cable landing stations in Japan and the US. PC Landing Corp was acquired by NTT in 2009. 


Ownership of Seren Juno
Ownership of Seren Juno


Seren was established as a special vehicle company for design, construction, sales and operations of the JUNO trans-Pacific submarine cable system.

Seren Juno establishes a wholly owned subsidiary Seren Juno Network America, Inc. (Seren Juno America), a company incorporated in California, the United States, as JUNO's landing party in the United States. Seren Juno America contracts with PC Landing Corp, the owner of Grover Beach CLS and Harbour Pointe CLS, to land the JUNO cable system at these cable landing stations.

NTT took the similar approach when building the MIST submarine cable connecting Singapore, Malaysia, Myanmar, Thailand, India. In 2019, NTT Ltd., Fund Corporation for the Overseas Development of Japan’s ICT and Postal Services Inc. (JICT) and WEN Capital Pte. Ltd. incorporated a strategic joint venture in Singapore, Orient Link Pte. Ltd. (OLL), as the owner of the MIST cable system.

JUNO, the new trans-Pacific submarine cable system, offers several unique benefits to customers:

  • It will introduce leading-edge SDM (Space Division Multiplexing) technology, enabling the provision of 20 optical fiber pairs (40 cores) per cable, (conventional technology currently provides a maximum of 16 fiber pairs or 32 cores).
  • It provides the maximum capacity of 350Tbps, the largest among any existing cable system between Japan and the US.
  • It offers high resiliency by connecting to two separate landing stations in between Japan and the US, providing additional security and resilience against any potential disturbances due to rough weather conditions, particularly along the coastal areas of Japan.
  • It provides flexibility, as JUNO can alter the amount of bandwidth to each branch route according to demand and in response to customers’ evolving requirements.

JUNO is expected to begin operating at the end of 2024.

JUNO Cable Route
JUNO Cable Route




NEC Corporation (NEC) announced on July 21, 2022 that it has been contracted by Seren Juno Network Co., Ltd. to build the JUNO Cable System connecting California in the US with Chiba prefecture and Mie prefecture in Japan. This cable will provide the largest data capacity between the US and Japan, spanning a total distance of approximately 10,000 km, and is expected to be completed by the end of 2024.