What Does Activating an eSIM Actually Mean?
To activate an eSIM in the UK, you scan a QR code provided by your network — your phone downloads the eSIM profile instantly, with no physical SIM card and no waiting for delivery. This guide walks you through the full process, including device-specific steps for iPhone, Samsung Galaxy, and Google Pixel.
Activation takes around two minutes from start to finish. There's no trip to a shop, no envelope to open, and no tiny plastic card to lose down the back of the sofa. Once your eSIM profile is downloaded, your phone connects to the network automatically.
With a Fuse Mobile eSIM, that connection happens across all four UK networks — EE, Three, Vodafone, and O2 — with your phone selecting whichever has the strongest signal wherever you are. If you haven't chosen a plan yet, take a look at Fuse's available plans before you begin.
Before You Start: Three Things to Check
Before you scan anything, run through these three checks. Skipping them is the most common reason activations fail.
1. Confirm Your Phone Is eSIM Compatible
Not every phone supports eSIM, though most devices released after 2018 do. Common compatible models include:
- iPhone: XS, XR, and all later models (including the full iPhone 15 and 16 ranges)
- Samsung Galaxy: S20 series onwards, plus many A-series and Z Fold/Flip models
- Google Pixel: Pixel 3 and later
- Other Android: Many recent handsets from OnePlus, Motorola, and Sony
If you're unsure whether your specific model supports eSIM, check the Fuse eSIM compatibility page for a full device list.
2. Make Sure Your Phone Is Unlocked
Your device must be unlocked — not tied to another UK carrier. If you bought your phone directly from Apple, Google, or a manufacturer's own website, it's almost certainly unlocked already. If you bought it through a network on contract, contact that network to request an unlock before proceeding.
Trying to activate an eSIM on a locked device is the single most common cause of activation errors.
3. Connect to Wi-Fi
You need a stable Wi-Fi connection to download your eSIM profile. Mobile data won't work for this step — you're essentially downloading the thing that gives you mobile data, so Wi-Fi is the only option. Home broadband, a café network, or office Wi-Fi all work fine.
How to Activate Your Fuse eSIM: Step-by-Step
Once you've signed up and chosen a plan, Fuse will send you an activation email containing your unique QR code. Keep that email open on another device — a laptop, tablet, or a second phone — so you can scan it with the device you're activating.
Important: Don't open the QR code email on the phone you're activating. You can't scan a QR code with the same screen it's displayed on.
The steps below are written generically first, then broken out by device type.
General Activation Process
- Open your phone's Settings app.
- Navigate to the mobile or cellular data section (the exact name varies by device — see below).
- Select the option to add a new eSIM or mobile plan.
- Choose Scan QR Code when prompted.
- Point your camera at the QR code in your Fuse activation email.
- Confirm the plan details when they appear on screen.
- Wait for the profile to download — this typically takes 10–30 seconds.
- Follow any remaining on-screen prompts to set the eSIM as your active data line.
That's the full process. The device-specific sections below show you exactly where to find each menu.
Activating on iPhone (iOS 17 and Later)
- Open Settings.
- Tap Mobile Data.
- Tap Add eSIM (or Add Mobile Plan on some older iOS versions).
- Tap Use QR Code.
- Scan the QR code from your Fuse activation email.
- Tap Continue on the plan confirmation screen.
- Wait for the eSIM profile to finish downloading.
- When prompted, choose whether to use this as your primary data line or keep it as a secondary line.
- Tap Done.
Your Fuse eSIM will now appear under Settings > Mobile Data alongside any existing SIM. You can label it (e.g. "Fuse") to keep things tidy.
Tip for iPhone 14 and 15 (US models): US variants of these phones are eSIM-only with no physical SIM tray. The steps above still apply — just note your phone may show slightly different wording around dual-SIM settings.
Activating on Samsung Galaxy
These steps apply to Samsung Galaxy devices running One UI 5 or later (Android 13+).
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- Open Settings.
- Tap Connections.
- Tap SIM Manager.
- Tap Add eSIM or the + icon in the top-right corner.
- Select Scan QR code from service provider.
- Scan the QR code from your Fuse activation email.
- Review the plan details and tap Confirm.
- Wait for the download to complete, then tap Done.
Once activated, your Fuse eSIM appears in SIM Manager alongside any physical SIM. To set it as your default for mobile data, tap it and select Set as default data SIM.
Activating on Google Pixel
These steps apply to Pixel devices running Android 12 or later.
- Open Settings.
- Tap Network & internet.
- Tap SIMs.
- Tap the + icon or Add SIM.
- When asked how you'd like to add a SIM, select Scan the QR code.
- Scan the QR code from your Fuse activation email.
- Follow the on-screen prompts to confirm and download the profile.
- Once complete, tap Activate to enable the eSIM.
Your Pixel will now show the Fuse eSIM under Settings > Network & internet > SIMs, where you can manage data preferences.
After Activation: What Happens Next
Connecting to the UK's Four Networks
Once your Fuse eSIM is active, your phone begins scanning for the strongest available signal from EE, Three, Vodafone, and O2. This happens automatically — there's nothing extra to configure.
In practice, this means that if you're in a building where one network has weak indoor coverage, your phone will switch to another. If you travel between cities, the same applies. You're not locked to a single mast or a single network's footprint.
You'll see the network name in the top corner of your phone's screen update as it switches. This is normal and expected — it's the multi-network switching working exactly as it should.
Checking Signal and Usage in the Fuse App
The Fuse app lets you monitor your data usage, check which network you're currently connected to, and manage your plan — all in one place. Download it from the App Store or Google Play after activation.
Inside the app you can:
- See your remaining data allowance in real time
- View your current connected network
- Upgrade or change your plan
- Contact support if something isn't working
If you want to head straight to activation now, go to fuse mobile's activation page.
Troubleshooting Common eSIM Activation Issues
My eSIM Isn't Showing After I Scanned the QR Code
First, check you're connected to Wi-Fi and that the connection is stable — a weak signal can interrupt the profile download. Restart your phone and try the scan again. If the eSIM still doesn't appear, go to your SIM or mobile data settings and check whether the profile downloaded but isn't yet enabled.
The QR Code Says It's Expired or Already Used
eSIM QR codes are single-use and may have an expiry window. If yours has expired or been used already, contact Fuse support via the help centre to request a new code — this is a quick fix and the team can reissue one promptly.
My Phone Says the eSIM Can't Be Added
This usually means your device is still locked to another carrier. Contact your previous network and request an unlock — most UK networks are legally required to unlock devices for free once any contract period has ended. Once unlocked, restart your phone and try the activation steps again.
The QR Code Won't Scan Properly
Make sure the screen displaying the QR code is at full brightness, and that you're holding your phone steady about 20–30 cm away. Avoid scanning in very bright sunlight or very low light. If the camera keeps struggling, try manually entering the activation code instead — most eSIM setup screens offer this as an alternative to scanning.
I've Activated but I Have No Signal
Check that the Fuse eSIM is set as your active data line (not just installed). On iPhone, go to Settings > Mobile Data and confirm Fuse is selected for data. On Samsung, check SIM Manager > Default data SIM. On Pixel, go to Settings > Network & internet > SIMs and confirm the eSIM is enabled. If signal still doesn't appear after 60 seconds, toggle aeroplane mode on and off to force a fresh network scan.
Frequently Asked Questions
How long does eSIM activation take?
The actual download and activation process takes around 10–30 seconds once you've scanned the QR code. From opening the Fuse sign-up page to having an active eSIM on your phone, most people are done in under five minutes.
Can I activate a Fuse eSIM without a QR code?
Yes — if your device supports manual entry, you can type in the activation code directly instead of scanning. The Fuse activation email includes both the QR code and the manual entry details. The option to enter a code manually appears on the same screen as the QR scanner in your phone's eSIM settings.
Will activating a Fuse eSIM remove my existing SIM?
No. Adding an eSIM doesn't affect your physical SIM or any existing eSIM profiles. Most phones support running two lines simultaneously — useful if you want to keep a personal number on one SIM while using Fuse for data. You simply choose which line handles calls, texts, and data in your phone's SIM settings.
Do I need to restart my phone after activating?
You don't always need to, but a restart is good practice if the eSIM doesn't connect to a network within a minute or two of activation. It forces your phone to re-scan for available networks and apply the new profile cleanly.
Can I try Fuse before committing to a paid plan?
Yes — Fuse offers a 7-day free trial so you can test the multi-network coverage before choosing a plan. Visit the free trial sign-up page to get started.
Ready to Activate?
Activating a Fuse eSIM takes just a few minutes: check your phone is compatible and unlocked, connect to Wi-Fi, scan your QR code, and you're live on all four UK networks. No physical SIM, no waiting, no fuss.
Head to the Fuse activation page to get your QR code, or visit the help centre if you run into any issues along the way.