# eSIM
> Embedded SIM – a digital SIM built into a device that can be programmed remotely

eSIM is a built-in digital SIM that allows remote activation of cellular plans without a physical card.

## What is eSIM?
An eSIM (embedded SIM) is a programmable SIM chip built directly into a smartphone, tablet, or wearable. Unlike traditional SIM cards, eSIMs can be activated and reconfigured remotely by downloading a carrier profile — no physical swap required.

## eSIM and VoIP
eSIM technology simplifies multi-line use cases. A user can maintain a cellular data plan via eSIM while running a [softphone](/voip-glossary/softphone/) for business calls over the same device. This is especially valuable for [BYOD](/voip-glossary/byod/) scenarios and international travelers.

## Related Terms
- [BYOD](/voip-glossary/byod/)
- [Softphone](/voip-glossary/softphone/)