miniSIMs

MiniSIM, also known as the 2FF SIM, is the second form factor of the SIM card. It measures 25 by 15 millimeters and has a thickness of about 0.76 millimeters. Introduced in the late 1990s, it became the standard size for mobile devices, replacing the larger full-size SIM used in earlier phones.

For much of the 2000s, miniSIMs were the dominant form factor until smaller sizes began to appear. With the introduction of micro-SIM (3FF) around 2003–2010 and nano-SIM (4FF) around 2012, manufacturers increasingly shifted to smaller cards. Today, miniSIMs are largely historical, found mainly in older devices.

A miniSIM stores the subscriber identity and network authentication data required to connect to a mobile operator’s network. It can also contain operator settings and, in some cases, stored contacts. The card is removable and can be transferred between devices, subject to operator compatibility and device recognition.

Despite its obsolescence, adapters exist to fit micro- or nano-SIMs into a device with a miniSIM slot. This means some users can reuse newer SIM cards in older hardware, though compatibility depends on the device and operator.

The emergence of eSIM technology—an embedded, non-removable SIM—further reduced the need for physical SIM cards of any size. As networks and devices continue to evolve, the miniSIM remains a historical reference point for early to mid-2010s mobile hardware.