What is a SIM and what does it identify?¶

A SIM may be recovered from a device or identified in provider records.

Evidential caution: that the SIM identifies the person who used the phone.

What this means¶

A SIM is a subscriber identity module used by a mobile network to recognise and authenticate a subscription. It may be a removable card or an embedded eSIM profile.

The SIM links the device to a mobile service. It may be associated with a telephone number, subscriber account and network records.

A SIM can be moved between devices, shared, borrowed, stolen or replaced. The subscriber may differ from the person who physically possessed it.

Consider whether the SIM was active, replaced, suspended or duplicated through an eSIM process.

In reports, distinguish the subscription identity from the device and user.

Where records disagree, retain the discrepancy and establish whether it reflects timing, replacement, transfer or collection method.

What to check or do next¶

• Preserve the SIM, its condition and the device in which it was found. Record the ICCID, IMSI, associated number, provider and relevant dates where available.
• Compare provider records showing which device identifiers used the SIM and when. This can help reconstruct movement between handsets.
• Do not infer that the person possessing the SIM at seizure used it during every earlier communication.
• Record the source of each identifier and preserve the original records so the relationship can be tested later.

Evidential limits¶

But it does not identify the human user by itself.