Glossary · Connectivity
eSIM
In one sentence
An eSIM is a SIM chip built into a phone or device. Instead of inserting a plastic card, the carrier downloads a subscription profile to it remotely, usually by scanning a QR code.
Also known as : eSIMs · embedded SIM · embedded SIMs · eUICC
What is an eSIM?
A SIM card exists to prove to the mobile network that you are the subscriber you claim to be. An eSIM (embedded SIM) does exactly the same job, but the chip is built into the device and never comes out. Instead of posting a card, the carrier sends a profile that holds the same identity data.
The standard is set by the GSMA, the global association of mobile operators. All major UK and Irish networks support eSIM on at least part of their range, as do many MVNOs, and the technology is also found in smartwatches, tablets, laptops and connected devices.
How it works
- The carrier creates a profile for the line and places it on a secure provisioning server.
- The user receives a QR code, or activates the line directly in the carrier’s app.
- The phone scans the code, connects to the server and downloads the profile into its eSIM chip, known as the eUICC.
- The line goes live: number, plan and network access behave exactly as they would with a physical SIM.
One chip can hold several profiles, with one or two active at once depending on the model. That makes it easy to keep separate work and personal numbers on one handset, or to add a local data profile when travelling outside the countries your plan covers for roaming.
Example
A facilities management company in Birmingham issues phones to 60 field engineers across the Midlands. With physical SIMs, every starter waited for a card in the post and every lost phone meant ordering a replacement. After moving to eSIM, the office manager emails a QR code through the company’s secure mail and the new line is active the same day. When someone leaves, the profile is cancelled remotely; nothing needs to be collected.
eSIM at Universal Telecom
Our business mobile plans are managed from one place and tie into the phone system. If staff only need a business number on their own phone, without a second mobile line, a virtual phone number used with a softphone app is another route. To check eSIM availability for your fleet, contact us.
Frequently asked questions
How do I know if my phone supports eSIM?
Most recent mid-range and flagship phones do, including iPhones from the XS onwards, many Samsung Galaxy models and Google Pixels. Look for an "Add eSIM" option in settings, or dial *#06#: an EID number appears if the device has an eSIM.
Is an eSIM more secure than a physical SIM?
It can't be removed and slipped into another phone if a device is stolen, which closes one route for misuse. Like any SIM, it still depends on your carrier's checks against SIM-swap fraud when a profile is moved to a new device.
Can I use an eSIM abroad?
Yes. You can keep your usual line and add a local or travel eSIM profile at your destination, which is often cheaper than roaming outside the countries your plan covers.
Related terms
- Roaming
Roaming lets you use your mobile line abroad on a partner operator's network. Within the EU and EEA, roam like at home rules apply domestic prices; UK networks have set their own charges since Brexit.
- MVNO (mobile virtual network operator)
An MVNO (mobile virtual network operator) sells mobile lines and plans without owning radio infrastructure. It rents capacity from a host network such as EE, Vodafone, O2 or Three and runs its own customers, tariffs and billing.
- Virtual phone number
A virtual phone number is a real phone number with no physical line behind it: calls are routed over the internet to a mobile app, a softphone or a phone system, wherever you are.
- Softphone
A softphone is a phone application that runs on a computer or smartphone. It replaces the desk phone and connects to the company phone system over VoIP, using the business number.
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