eSIM Technology Overview and Recent Service Suspensions in China

eSIM (Embedded‑SIM) embeds the SIM directly into a device’s chipset, eliminating the need for a removable card and allowing users to switch carriers without changing physical SIMs.

Since the first commercial SIM in 1991, SIM cards have evolved from Standard to Nano, and now eSIM represents the digital upgrade trend, removing the physical card entirely.

Apple pioneered eSIM adoption, first introducing the concept with Apple SIM on iPad Air 2 in 2014, then dual‑SIM iPhones in 2018, and fully eSIM‑only iPhone 14 models in some markets, while Chinese iPhone 14 retains dual nano‑SIM slots.

In late May, China Mobile announced a pause on eSIM watch dual‑terminal services for maintenance, with similar suspensions from China Unicom and China Telecom, affecting new eSIM watch activations in several provinces.

The "one‑number dual‑terminal" service, launched in 2018, lets a phone and a wearable share the same number, billing, and data plan, so calls and messages ring on both devices.

An "independent eSIM" allows a watch to have its own number, functioning completely separate from the phone.

Speculation suggests the service was halted due to a bug that could convert eSIM profiles back to physical SIMs, leading to potential fraud; some users have even demonstrated extracting eSIM chips to create physical cards.

eSIM poses greater information‑security challenges than traditional SIMs because remote provisioning can bypass robust identity verification, increasing the risk of telecom fraud.

Consumers are advised to verify eSIM support with their carriers before purchasing Android smartwatches, as the primary feature may be unavailable.