Monitored from 2026-07-28 through 2026-08-29 - live ICMP round-trip time measurements via our monitoring probes. All values below are recomputed daily from raw probe data. ✓ No anomalies detected in the monitored period.
Measurement sources
Probe
Location
Samples
Avg
Min-Max
Last seen
#6410 own probe
Sao Paulo BR
18
330.8 ms
306.1-497.4
2026-08-29
#6487 own probe
Singapore SG
18
31.7 ms
30.7-34.1
2026-08-29
#1014589 own probe
Almaty KZ
18
271.0 ms
263.0-292.4
2026-08-29
#1014597 own probe
Tbilisi GE
1
358.0 ms
358.0-358.0
2026-08-29
About the Hainan to Hong Kong Express (H2HE) Cable System
Hainan to Hong Kong Express (H2HE): A regional submarine cable connecting southern China
The Hainan to Hong Kong Express (H2HE) is a submarine telecommunications cable system spanning 675 kilometers, linking key locations in southern China: Chung Hom Kok in Hong Kong, Wenchang in Hainan Province, and Zhuhai in Guangdong Province. Owned by China Mobile, the cable is listed as in service and was recorded as ready for service (RFS) in 2021 according to GeoCables database records. It is part of the growing network of regional cables facilitating connectivity within East Asia.
What makes this cable noteworthy is its role in connecting Hainan Island to mainland China and Hong Kong, a corridor with increasing strategic importance for domestic and international telecommunications. However, public information about its design capacity, fiber pairs, supplier, and specific technology is not disclosed, leaving some technical aspects of the system open to speculation.
Quick facts
System name
Hainan to Hong Kong Express (H2HE)
Length
675 km
Ready for service
2021 (GeoCables database)
Owner
China Mobile
Status
In service
Design capacity
Not disclosed
Fiber pairs
Not disclosed
Supplier
Not disclosed
Technology
Not disclosed
Landing points
Chung Hom Kok (Hong Kong), Wenchang (Hainan), Zhuhai (Guangdong)
The H2HE cable connects three landing points: Chung Hom Kok in Hong Kong, Wenchang in Hainan Province, and Zhuhai in Guangdong Province. Chung Hom Kok is a well-established cable landing site in Hong Kong, hosting multiple other submarine cables such as Asia Direct Cable (ADC), Asia Link Cable (ALC), EAC-C2C, Southeast Asia-Japan Cable 2 (SJC2), and Southeast Asia-Japan Cable (SJC). Wenchang, located on the northeastern coast of Hainan Island, is a growing hub for submarine cable landings, while Zhuhai in Guangdong Province serves as a mainland China landing point, strategically close to the Pearl River Delta's economic zone.
Why it was built and what it carries
The H2HE cable was likely built to enhance regional connectivity between Hainan, Hong Kong, and mainland China, supporting the increasing demand for high-speed data transmission in southern China. Hainan Island, in particular, has been undergoing significant development, including its designation as a free-trade port, which necessitates strong telecommunications infrastructure. The cable also provides additional redundancy for existing systems in the region, ensuring more reliable connectivity in case of disruptions.
While the specific types of traffic carried by H2HE are not disclosed, submarine cables in this corridor typically support internet, voice, and enterprise data services. Given China Mobile's ownership, the cable likely plays a role in the company's domestic and international network operations.
History: what can be established
According to GeoCables records, the H2HE cable was ready for service in 2021. No conflicting dates have been identified in publicly available industry sources, so this date is treated as accurate. However, details about the cable's construction timeline, supplier, and commissioning process are not publicly documented.
Capacity and technology
The design capacity of the H2HE cable is not disclosed, nor are the number of fiber pairs or the specific technology used in its construction. Without operator documentation, attributing these details would be speculative. Submarine cables of this length and regional importance typically employ dense wavelength division multiplexing (DWDM) technology to maximize data throughput, but this cannot be confirmed for H2HE.
Latency: the physics
The computed one-way light propagation latency for the 675 km wet segment of the H2HE cable is approximately 3.3 milliseconds, with a theoretical round-trip time (RTT) floor of 6.6 milliseconds. These calculations assume light traveling through fiber at speeds between 200,000 and 204,000 km/s. However, real-world RTT measurements would be higher due to additional latency introduced by land-based tails, terminal equipment, and routing. No live measurements for H2HE are currently available.
Redundancy: what happens if it breaks
If the H2HE cable were to experience a disruption, redundancy in the region is supported by several other submarine cables landing at Chung Hom Kok, including the Asia Direct Cable (ADC), Asia Link Cable (ALC), EAC-C2C, Southeast Asia-Japan Cable 2 (SJC2), and Southeast Asia-Japan Cable (SJC). These systems provide alternative routes for traffic between Hong Kong and other parts of Asia. Repairing submarine cables typically involves deploying specialized cable ships to locate, retrieve, and repair the damaged section, a standard practice in the industry.
Bottom line
The Hainan to Hong Kong Express (H2HE) is a 675 km submarine cable connecting Hong Kong, Hainan, and Guangdong.
Owned by China Mobile, it was recorded as ready for service in 2021.
Publicly available data does not disclose its design capacity, fiber pairs, supplier, or technology.
Its theoretical round-trip latency over the wet segment is approximately 6.6 milliseconds.
Redundancy is provided by other cables landing at Chung Hom Kok, Hong Kong.