Frequently Asked Questions & Glossary
This page answers the most common questions we receive from UK travellers about eSIM technology, and provides a comprehensive glossary of technical terms used throughout this site. Use the glossary links throughout our pages to jump directly to a definition.
Frequently Asked Questions
What devices support eSIM?
Most flagship smartphones released after 2018 support eSIM, including iPhone XS and later, Samsung Galaxy S20 and later, Google Pixel 3 and later, and many others. Check your device specifications or go to Settings and look for an "Add eSIM" option. Budget devices and some carrier-exclusive models may not include eSIM hardware.
Can I use an eSIM and my regular SIM at the same time?
Yes, on dual-SIM devices. You can keep your UK home SIM active for calls and SMS while using the eSIM for local data. This is the most common and recommended configuration for travellers.
Will my eSIM work immediately after scanning the QR code?
The profile installs immediately, but data connectivity may not activate until you arrive in the destination country, depending on the carrier's plan terms. Some carriers activate globally; others activate only upon first connection to a local network.
What happens if I lose my phone with an eSIM installed?
Contact the carrier immediately to suspend the eSIM profile. Most carriers can deactivate a profile remotely. Your home SIM and eSIM are independent — losing the device does not affect your home account.
Can I reuse an eSIM plan on a different device?
Generally, no. eSIM profiles are tied to the device on which they were installed. Some carriers allow one transfer, but this is not universal. Always check the carrier's transfer policy before purchase.
How do I check my remaining data balance?
Most carriers provide a companion app or a web portal for balance checking. Some plans also send SMS alerts when you reach 80% and 100% of your data allowance. Check the carrier's documentation for the specific method.
Is eSIM safe and secure?
Yes. eSIM profiles are transmitted using end-to-end encryption between the carrier's SM-DP+ server and your device's LPA. The profile cannot be intercepted or cloned during transmission. Physical theft of your device is the primary security risk, mitigated by device lock and remote wipe features.
What should I do if my eSIM stops working mid-trip?
First, toggle aeroplane mode off and on. If that fails, go to Settings and manually select the carrier network. If the issue persists, contact the carrier's support team. As a backup, connect to hotel or café Wi-Fi and use VoIP for communication while resolving the issue.
Can I get a refund if my eSIM doesn't work?
Refund policies vary by carrier. Most carriers offer a refund if the eSIM fails to activate through no fault of the user. Refunds for unused data after successful activation are rare. Always read the refund policy before purchase.
Do eSIM plans include a UK number?
No. Travel eSIM plans are data-only in the vast majority of cases. Your UK number remains on your home SIM. You can receive calls on your UK number while using eSIM data, provided your device supports dual-SIM operation.
Glossary of eSIM Terms
- eSIM
- An embedded SIM card built into your device that can be programmed remotely without a physical SIM swap.
- IMSI
- International Mobile Subscriber Identity — a unique number identifying a mobile subscriber.
- Roaming
- Using your mobile network while abroad, typically at higher rates unless a roaming plan is active.
- APN
- Access Point Name — the gateway between a mobile network and the internet, sometimes needing manual configuration.
- QR Code Activation
- The standard method to install an eSIM profile by scanning a QR code provided by the carrier.
- Dual SIM
- A device capability allowing two SIM profiles (physical + eSIM, or two eSIMs) to be active simultaneously.
- LPA
- Local Profile Assistant — the software on your device that manages eSIM profile downloads and activation.
- SM-DP+
- Subscription Manager Data Preparation — the server that securely delivers eSIM profiles to devices.
- Data-Only eSIM
- An eSIM plan that provides mobile data without a voice or SMS number, ideal for travellers using VoIP apps.
- Coverage Map
- A visual representation of geographic areas where a carrier's network signal is available.