What is the difference between a handset, SIM, eSIM and mobile subscription?¶
A handset is the physical device.
What this means¶
A SIM is a removable chip that allows a device to authenticate to a mobile network.
An eSIM performs a similar function but is built into the device and activated through a digital profile rather than a removable card.
A mobile subscription is the service agreement or account provided by the network. It may include a telephone number, data allowance, billing details and subscriber information.
These elements are related, but they can change independently.
A handset can be used with different SIMs. A SIM can be moved between handsets. An eSIM profile can be activated, replaced or transferred. A telephone number can be ported to another provider. A subscription can be registered to one person while the handset is used by somebody else.
The handset has its own identifiers, such as an IMEI. The SIM or subscription has separate identifiers, such as an IMSI or ICCID. These identifiers can help link devices, subscriptions and network activity, but none automatically identifies the human user.
Investigatively, record the handset details, the visible number, the SIM or eSIM status, the network provider and any account information. Do not remove a SIM or alter the device unless that action is justified and safe, because it may change the device state, affect connectivity or complicate later examination.
Where several SIMs, eSIM profiles or handsets are involved, build a timeline showing which subscription was associated with which device at the relevant time.
The operational takeaway is: separate the physical handset, network credential and service subscription. Then use provider, device and contextual evidence to establish how they were connected and who was actually using them.
Evidential limits¶
The SIM or eSIM normally contains identifiers used by the network, but it does not contain a complete copy of the subscriber’s activity. Most modern evidence sits on the handset, with the network provider, in application accounts or in the cloud.