What is the difference between a handset, SIM, eSIM and mobile subscription?¶

The handset is the physical device; a SIM or eSIM profile supplies a network credential; the mobile subscription is the provider service and account behind that credential.

Each component has its own identity¶

The handset commonly has an IMEI. A removable SIM and a digitally installed eSIM profile have identifiers such as ICCID and IMSI associated with network authentication. The subscription can include a telephone number, billing arrangement and subscriber details. Modern devices may hold several physical or embedded profiles.

These relationships change: SIMs move between handsets, eSIM profiles are transferred or reissued, numbers are ported and a registered subscriber may not be the user. A SIM normally does not contain a complete activity history; relevant records are distributed across handset, network, apps and cloud services.

Reconstruct the relevant-time combination¶

Record the handset, visible number, provider, SIM or eSIM state and source of every identifier. Do not remove or change a profile merely to identify it, because connectivity and device state may change.

Where several subscriptions or devices appear, build a timeline showing which credential used which handset. The IMEI, IMSI and ICCID then connect different parts of that relationship without identifying the human user alone.