Unlocked vs Network Phones Explained (UK Guide)

29 October 2026

If you've ever looked at a phone listing and wondered what "unlocked", "SIM-free" or "locked to EE" actually mean for you, this guide is for you. Here's the plain-English version, with real prices from our own stock, so you can buy the right phone first time.

The short answer

An unlocked phone works with a SIM card from any UK network: EE, Vodafone, O2, Three, or any of the smaller networks that run on them, such as giffgaff, Tesco Mobile, Lebara, Smarty or VOXI. A network-locked phone only accepts SIMs from the network it was sold for until it's unlocked. For most people, unlocked is the better buy: you can switch to a cheaper SIM deal whenever you like.

Unlocked, SIM-free and contract: what's the difference?

  • Unlocked: the phone isn't tied to any network. Put any SIM in and it works.
  • SIM-free: the phone is sold without a SIM card or airtime. Almost every SIM-free phone sold new in the UK today is also unlocked, but always check the listing.
  • Contract (or "network") phone: you get the handset as part of a monthly plan, usually over 24 to 36 months. You pay for the phone inside the bill.
  • Network-locked: the phone only accepts one network's SIMs. You mostly see this on older stock, pay-as-you-go packs and second-hand phones.

Do UK networks still lock phones?

Not on new phones. Since December 2021, Ofcom rules have stopped UK mobile networks selling locked handsets, so a phone bought new from EE, Vodafone, O2 or Three now arrives unlocked. Older phones are a different story: plenty of handsets made before then, and some pay-as-you-go packs still sitting in stock, are locked to the network they were made for. That's why you'll see "(EE)" or "(Vodafone)" in the titles of some of our listings.

Why buy unlocked?

  • Cheaper monthly bills. Pairing an unlocked phone with a SIM-only deal is usually cheaper over two years than a handset contract, and you aren't tied in.
  • Freedom to switch. If your signal is poor at home or a better deal comes along, change network without changing phone.
  • Travel. Pop in a local SIM or an eSIM abroad instead of paying roaming charges.
  • Better resale value. Unlocked phones are easier to sell or pass on to family.

When a locked phone still makes sense

A network-locked phone is fine if you already use that network and just want a cheap, simple handset. Our Alcatel 1054X on Vodafone is £28.99 and the Nokia 108 on EE is £29.99: ideal as a spare phone or for an older relative who's been with the same network for years. If you're not sure which network you'll use, spend a little more on an unlocked phone instead.

Our unlocked picks by budget

Under £50: simple phones for calls and texts

The Nokia 106 (£26.99) and the Nokia 225 4G (£49.99) both take any UK SIM. Go for a 4G model if you can: UK networks have switched off 3G and 2G won't be around forever. See all of our budget phones under £50.

£100 to £200: a first smartphone

The Samsung Galaxy A07 64GB (£119.99) is brand new, unlocked and covers WhatsApp, maps and banking apps. If you'd like 5G and more storage, the Galaxy A17 5G 128GB is £188.99. Prefer an iPhone? A refurbished iPhone SE (2022) is £120.99 with a 12-month XTEC warranty.

£200 to £350: the sweet spot

A refurbished iPhone 13 128GB at £249.99 or a brand new Galaxy A37 5G at £269.99 will do everything most people need for years. Browse all Samsung phones or our refurbished range.

Are refurbished phones unlocked?

When one of our refurbished phones is tied to a network, we name it in the title (for example "EE" or "Vodafone"). If you're unsure about a particular phone, ask us before you order. Every XTEC Renewed phone is tested, data-wiped and graded before it goes on sale. Read how we grade refurbished devices to see what Pristine, Excellent and Good mean.

How to check if a phone is unlocked

  1. Borrow a SIM from a different network to yours and put it in the phone.
  2. Restart the phone.
  3. If you get signal bars and can make a call, it's unlocked. If you see "SIM not supported", "Invalid SIM" or a request for an unlock code, it's locked.

On an iPhone you can also go to Settings > General > About and look for "Carrier Lock: No SIM restrictions".

Can I unlock a locked phone?

Usually, yes. Ask the network the phone is locked to for an unlock code. The main UK networks unlock phones for free once any contract on that handset has ended, though it can take a few working days. Avoid paid "unlocking" websites that ask for your account details.

Quick checklist before you buy

  • Does the listing say unlocked, or name a network?
  • Is it 4G or 5G? Avoid 3G-only phones in the UK now.
  • Does it take the SIM size you have (most phones use nano-SIM; many now support eSIM too)?
  • What warranty comes with it? Brand new phones come with the manufacturer warranty; our refurbished phones come with a 12-month XTEC warranty.

Still not sure? Message us on WhatsApp on 07599 803768 and we'll point you to the right phone.