India, Nov. 24 -- Africa's coastline is witnessing a power shift, one unfolding not through gunboats or military bases, but through cables, code and cloud-linked systems. Beijing's presence in the Western Indian Ocean, once defined by the naval base in Djibouti and commercial stakes in Gwadar, has quietly entered a more consequential phase. China is now embedding itself in the digital infrastructure that runs African ports, customs networks and coastal surveillance systems, creating what officials and analysts describe as a new form of strategic depth.

The change has been a decade in the making. Chinese firms, led by Huawei Marine (now HMN Tech), ZTE, China Harbour Engineering Company and China Merchants Port Holdings, have steadily won ...