As eSIM technology gains traction, a growing number of users are embracing phones that come with eSIM capabilities. Yet, it's important to note that each eSIM-enabled phone can only activate up to two numbers at the same time. Some individuals who sell their second-hand devices neglect to deactivate their original numbers or swap out SIM cards promptly. This oversight can hinder new users from activating eSIM services as they should. To tackle this challenge, China Unicom unveiled, on April 8, 2026, the introduction of an eSIM query feature.

Through this feature, users can verify, either via the eSIM section of the China Unicom App or by dropping by a business hall, if their current device has hit the eSIM number cap (which stands at two per device). They can also check if the number of new eSIM activations within a month has peaked (capped at two times per month), and ascertain the China Unicom eSIM numbers or the total count currently tied to their device (for numbers associated with other operators, users are advised to reach out to those operators directly).

For user-initiated queries, simply navigate to the China Unicom App, head to the eSIM section, select Other Services, and then opt for Query Number of eSIM-Bound Phone Numbers. Here, you can input or scan your phone's EID and IMEI codes. On the business front, queries can be processed in the CBSS system. Just access the "User Query - eSIM Query" portal and enter the EID to gain insights into the status of service numbers and the number of activations within the calendar month.