eSIM (Embedded SIM) is a rewritable SIM built into smartphones and tablets. Unlike traditional physical SIM cards, carrier information (profiles) can be written online without swapping cards. Based on international standards established by the GSMA (GSM Association), major manufacturer devices support it, including iPhone XS (2018) and later, Google Pixel 3 and later, and Samsung Galaxy S20 and later.
The greatest advantages of eSIM are immediacy and flexibility. You can activate a line instantly online without visiting a store, starting service in just minutes by scanning a QR code. Multiple eSIM profiles can be stored on a single device, enabling dual SIM use to manage work and personal numbers on one phone, or adding a local eSIM plan when traveling abroad to avoid expensive roaming charges. Eliminating the physical SIM slot also contributes to improved device waterproofing and better use of internal space.
The choice between eSIM and physical SIM depends on the use case. eSIM excels at instant activation and managing multiple lines, but transferring profiles when a device breaks down is more cumbersome than with physical SIM. Physical SIM offers easy swapping between devices and the simplicity of buying a local SIM at an overseas airport for immediate use. iPhone 14 (US model) and later have eliminated the physical SIM slot entirely, making the transition to eSIM an irreversible trend.
When switching to eSIM via MNP, some carriers require EID (eSIM identification number) registration. The EID can be found under Settings > General > About (iPhone) or Settings > About Phone (Android). MVNO (budget SIM) support for eSIM is also expanding, with IIJmio, Rakuten Mobile, LINEMO, and others offering eSIM plans. Review switching procedures in the number portability guide.