Fresim

What Is an eSIM?: eSIM & Mobile Connectivity Explained

An eSIM is a digital SIM built into your phone. Learn how it works, which phones support it and how travellers install one with one tap in minutes on arrival.

Updated 16 October 2026

In one sentence

An eSIM (embedded SIM) is a SIM built into your phone as a tiny chip, so you can add a mobile plan digitally instead of swapping a plastic card.

In detail

A traditional SIM is a small plastic card that holds the details your phone needs to join a mobile network. An eSIM does the same job, but the chip is soldered inside the device and is rewritable, so a plan is downloaded as a digital profile rather than inserted by hand. Most modern phones, tablets and smartwatches support eSIM, and many can store several profiles at once, for example your home plan plus a travel data plan. The standards behind this are set by the GSMA, the global mobile industry body, which is why eSIM works across brands and countries. You never lose or bend an eSIM, and you do not need a SIM-ejector pin or a shop visit to use one.

How it works

Inside an eSIM-capable phone sits a secure chip called an eUICC, which can store and switch between multiple network profiles. When you buy an eSIM plan, the profile is delivered to your device over the internet and installed on that chip. Your phone then connects to a local network just as it would with a physical SIM.

Why travellers should care

With an eSIM you can buy mobile data for your destination before you leave and skip airport kiosks, local shops and tiny SIM cards. Because the chip is separate from your home plan, you can keep your usual number available while using a local data plan abroad. Plans on Fresim-powered stores cover 190+ destinations, and prices vary by destination and are set by each store.

Related terms

  • SIM card
  • eUICC
  • QR code activation
  • Dual SIM
  • Data roaming

Example

Priya is flying from Sydney to Lisbon with an iPhone. Before boarding, she buys a Portugal data eSIM from a creator's Fresim store and receives it by email. She taps Install on iPhone (iOS 17.4+), and the plan is added to her phone. When she lands, she switches on the travel plan for data and keeps her home number for calls. If she wants to install it on another phone, she can scan the QR code from the email on a second screen.

Key takeaway

An eSIM is a SIM you download instead of insert, which lets travellers get mobile data for a destination in a few taps.

Frequently asked questions

What is an eSIM?

An eSIM is a SIM built into your phone as a small chip, which lets you add a mobile plan digitally without a physical card. Instead of inserting plastic, you install a plan delivered by email or app. With Fresim-powered stores, you tap Install on iPhone (iOS 17.4+) or Install on Android (Android 10+) and the eSIM installs. The QR code is a second option, handy for sharing the eSIM or installing from another screen.

What is an eSIM card?

An eSIM card is not a physical card at all; it is a digital SIM stored on a chip already inside your device. People say eSIM card because it replaces the plastic SIM card, but there is nothing to hold or insert. Your plan arrives as a digital profile, installed with one tap or by scanning a QR code.

Is an eSIM better than a physical SIM for travel?

For most travellers, an eSIM is more convenient because you can set it up before you leave and nothing needs to be swapped. You also keep your home SIM or eSIM active in the same phone, so you do not have to store a tiny card. A physical SIM can still make sense if your phone does not support eSIM or you need a local number with a specific carrier.

Which phones support eSIM?

Many recent phones support eSIM, including iPhone XS and later and a wide range of Android phones. Check your phone's settings or manufacturer page to confirm, and make sure your phone is not locked to one carrier. For one-tap install on Fresim-powered stores, you need iOS 17.4 or later on iPhone, or Android 10 or later on Android.

Can I use an eSIM and keep my home number?

Yes, most eSIM-capable phones can hold more than one plan and use them at the same time. You can keep your home plan for calls and texts while a travel eSIM handles mobile data abroad. In your phone's settings, you choose which plan is used for data, and you can switch it back when you return home.

Where you'll use this

More esim glossary

Sources

  • GSMA — Embedded SIM (eSIM) Specifications and Consumer Remote SIM Provisioning
  • Apple Support — About eSIM on iPhone
  • Google Android Help — Use an eSIM on your Android phone