The South-East Asia Hainan-Hongkong Express Cable System (SEA-H2X) is a submarine cable connecting Hong Kong SAR China, Hainan China, the Philippines, Thailand and Singapore.

The SEA-H2X consortium comprises China Mobile International Limited (CMI), China Unicom Global (CUG) , Converge Information and Communications Technology Solutions, Inc. (Converge). The SEA-H2X Consortium selects HMN Technologies Co., Limited (HMN Tech) to build the system.

The Construction and Maintenance Agreement (C&MA) and Supply Contract for the SEA-H2X project were effective on March 4, 2022, and come into force as of May 12, 2022.

When the SEA-H2X project was announced in 2022, the Malaysian operator PPTEL (now doing business as irix) was a member, to land the cable in Kuching, Sarawak. PPTEL (irix) owns and operates the Batam Sarawak Internet Cable System (BaSICS) connecting Sarawak (Malaysia) and Batam (Indonesia). According to the latest announcement by the SEA-H2X consortium, PPTEL (irix) has quit. And the originally designed branch to Kuching in Malaysia hasn't been deployed.

The SEA-H2X cable system consists of 8 fiber pairs between Hong Kong SAR and Singapore, with a design capacity of 200 Tbps to meet the growing bandwidth requirement in the region. Employing an open system model, SEA-H2X has the flexibility to choose best-in-breed Submarine Line Terminal Equipment (SLTE) from third-party vendors at a later date. HMN Tech’s advanced Branching Unit (BU) and Reconfigurable Optical Add/Drop Multiplexer (ROADM) benefits SEA-H2X in providing the ultimate flexibility of electrical power and optical fiber switches across multiple locations.

The SEA-H2X cable system has been ready-for-service as of May 26, 2026, commercially activated on July 22, 2026.

The SEA-H2X enables diverse connections to the Hainan Free Trade Port, in additional to the Hainan to Hong Kong Express (H2HE) submarine cable system and the Asia Link Cable (ALC).