Mozillion vs iD Mobile: which SIM only deal is right for you?
Picture it: two browser tabs open, one for Mozillion and one for iD Mobile, trying to work out what really sets them apart. On the surface they share a fair bit. Neither will put your price up mid-contract, both give you unlimited calls and texts, and both let you pick 1, 12 or 24 months. Look a little closer, though, and the two start to pull in quite different directions, and that’s where the real decision lives.
We reckoned the fairest way was to put the two side by side on the things you’ll actually notice once the SIM is in your phone, and let you decide.
The quick version, side by side
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|---|---|---|
| Network | Runs on the UK’s Best Network | VodafoneThree (Three + Vodafone) |
| Credit check | No credit check | Credit check on Pay Monthly |
| Plan lengths | 1, 12 or 24-months | 1, 12 or 24-months |
| Data rollover | No | Yes |
| EU roaming | 41 destinations | 50 destinations |
| Travel beyond Europe | Wallet top-ups, Travel eSIM in 200+ destinations, plus Global eSIM | Roam Beyond data add-ons |
| Can your shopping pay your bill? | Yes, with Kill Your Bill | No, partner discounts |
Getting set up, and what each one asks of you first
Before you get anywhere near the clever features, there’s the small matter of signing up, and this is the very first place the two part ways.
iD Mobile runs a credit check when you take out a Pay Monthly plan. For most people it’s a quick formality they’ll never give a second thought. It’s only really worth flagging if you’d rather not add a search to your credit file just now, say with a mortgage or loan on the horizon.
Mozillion skips the credit check on its SIM only plans completely, and honestly, this is where it starts to feel a little bit magic. You pick a plan, pay, and if your handset takes an eSIM you can be live in about a minute, your own number and all. No card in the post, no waiting around for an activation text, no “please allow up to 24 hours”. Just a working SIM before the kettle’s even boiled. The first time you do it, you half expect something to go wrong, and it just… doesn’t.
The network underneath the SIM
A SIM is only ever as good as the network carrying it, and this is one of the biggest differences between the two.
iD Mobile is owned by Currys and runs on Three, which teamed up with Vodafone in 2025 to become VodafoneThree. It’s a solid network that loads of people are perfectly happy on, especially around towns and cities.
Mozillion, though, runs on the UK’s Best Network, and that’s not us being clever with words. It’s the title independent RootMetrics testing has handed it for 13 years running. In the latest round, covering the first half of 2026, it swept the board: top overall, fastest, most reliable, and best for calls, video and 5G. When your train pulls out of the station and the video call doesn’t so much as flinch, that’s the bit you’re feeling.
That said, signal is a wonderfully local thing. We’ve all got that one corner of the house where messages go to die. So before you commit either way, spend ten seconds dropping your home, your work and your weekend spots into our coverage checker. It tells you the only thing that really counts: what you’ll actually get, where you actually are.
iD’s clever touches with your data
Here’s where iD Mobile really deserves a tip of the hat, because it’s clearly sweated the small, everyday stuff.
Top of the list is Data Rollover. Anything you don’t use rolls into next month, so a quiet stretch spent mostly on Wi-Fi doesn’t just vanish into thin air. Pair that with free bill capping as standard, which lets you set a hard ceiling on anything outside your plan, and you’ve got a setup that quietly looks out for you. They’re little things on paper, but they’re exactly the little things you’re thankful for when life does its thing.
Mozillion plays it differently. No rollover here, but every single plan comes with uncapped 5G, so you’re getting the network’s full speed across all of your data. Less about banking the scraps you didn’t use, more about making the most of what you do.
So it’s really a question of temperament: iD rewards the careful, tidy month, while Mozillion keeps it simple, with uncapped 5G on every plan.
When the trip goes further than Europe
For a long weekend in Spain or a city break in Lisbon, you’re sorted either way. iD Mobile throws in roaming across 50 destinations, a few more than Mozillion’s 41, so for a classic European trip it nudges ahead on the map.
Leave the continent, though, and things shift. Past those 50 destinations, iD has you buying Roam Beyond data add-ons for each place as you go. Mozillion comes at it with a proper travel kit: a dedicated Travel eSIM with data in more than 200 destinations, a Global Travel eSIM that keeps a whole multi-country trip on one eSIM, and wallet top-ups if you’d rather pay as you go. It all sits in the Travel eSIM app, so bouncing through, say, Thailand, Singapore and Japan doesn’t mean wrestling a new SIM at every border.
We’ll admit a soft spot for this one. Landing off a long-haul flight with your maps and messages already up, instead of squinting at “airport free Wi-Fi: 1 device, 30 minutes”, makes that first bleary hour in a new country so much kinder. And your usual SIM stays live alongside it for calls and texts, so nobody back home loses track of you.
Two very different takes on rewards
Both hand you something back for being a customer, and each has its own rewards system of partner offers to dip into.
iD Mobile has iD Perks: a rotating spread of discounts and offers from big names like Booking.com, The AA, Morrisons and Disney, all claimed through the iD app. There’s no cap on how many you grab, and the line-up keeps changing, so it’s well worth a peek before you book a holiday or tackle the big shop.
Mozillion has its everyday rewards too, but it doesn’t stop there. On top of them sits Kill Your Bill, and this is the one we get properly excited about, because it goes after your phone bill itself, not a shop’s price tag. Here’s the trick:
Buy a gift card first
Before you pay at any of 200+ brands, grab a gift card for that shop in the Kill Your Bill app. Takes seconds.
Shop exactly as normal
Pay with it at the till or online. Same shop, same basket, same total you were going to spend anyway.
Watch your bill drop
A reward lands straight on your phone bill. Earn more than your bill in a month? The extra rolls over, and never expires.
Run a bog-standard week through it, the big supermarket shop, a couple of coffees, the Friday night takeaway, and your bill genuinely starts melting away. For some households it hits nothing at all. A perks discount shaves a few quid off here and there, which is lovely; Kill Your Bill takes aim at the whole bill. We’re not aware of another UK network pulling off quite the same on its SIM only plans, and watching the Sunday shop wipe out a month’s bill never really gets old.
Plans, and how far they bend to fit you
On plan lengths it’s a dead heat, 1, 12 or 24-months whichever you choose. Where Mozillion stretches its legs is in how you pay, and who the plans are made for.
Next to standard Pay Monthly there’s Pay as you go, and Pay Monthly Plus, a neat middle option where you put half down up front and spread the rest, landing you a lower total than standard Pay Monthly. And if the phone’s for work, Mozillion’s got dedicated Business SIM only plans, priced without VAT and on rolling one-month terms, so a sole trader or a small team can add or drop a line whenever things change.
iD keeps it refreshingly simple, Pay Monthly or Pay as you go, which for plenty of people is exactly enough.
The high-street factor
There’s one thing Mozillion simply can’t hand you: a shop you can walk into. And for some people, that’s worth more than anything on a spec sheet.
Because iD Mobile is part of Currys, it’s got a big, familiar high-street name standing behind it, with its plans sitting right alongside Currys’ phones and accessories. If you like sorting your phone face to face, or just knowing there’s somewhere real to take a question, that’s a proper tick in iD’s column. It’s also got a lively online community and help centre for the types who’d rather crack things themselves.
Mozillion goes the other way, online-first, with a support team on hand seven days a week. Leaner, quicker to set up, but no store on the corner. Whether that’s a win or a wobble is entirely down to how you like to get things done.
So, where does that leave you?
Both are cracking SIM only choices, so the honest answer is the slightly annoying one: it depends on what you want most. Here’s the quick gut-check.
iD Mobile could be your pick if…
Mozillion is likely the better fit if…
Reviews from Mozillion customers that made the switch
Mozillion have been great
“Mozillion have been great. Good service. Even better travel SIM deals. They remind you re your debit order. I have had no issues and pleased that I switched when I did!”
Read more →Easy to set up.
“Easy to set up. No problems getting number switched over. App for kill your bill had to be reinstalled to make the first voucher purchase which was a little faffy, but not particularly a problem. Have now used the app for voucher purchase from Aldi and used said voucher against my bill 👌🏻”
Read more →Switching to Mozillion was super easy
“Switching to Mozillion was super easy, SIM card sent out quick, and within 18hrs my number was switched and I was up and running. Up to now, my coverage seems to be loads better than my previous supplier. Hopefully it stays that way and I’ll be well pleased.”
Read more →
