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How UK mobile networks work

The difference between locked and unlocked

I already have a mobile plan/network

I don’t have a mobile plan/network yet

How to activate my phone after purchase

How UK mobile networks work

In the UK, the main networks (MNOs) are EE, O2, Vodafone UK, and Three. They own and operate the network infrastructure and sell plans directly.

Other brands like giffgaff, Tesco Mobile, Sky Mobile, VOXI, Lebara, Lycamobile, SMARTY, iD Mobile, and Talkmobile are MVNOs — they use one of the Big 4 networks to provide service.

MVNOs can be great value and flexible. As with any network, check coverage in your area and whether your device supports the UK bands used by your chosen network.

The difference between locked and unlocked

When buying a refurbished phone, there are pros and cons to both locked and unlocked models. Back Market sells both.

Unlocked phones can work with any compatible UK network. Locked phones only work with the specific network they’re locked to. For the best experience, choose a model that’s fully compatible with your chosen UK network and bands.

A device originally sold by one network may work on another if it’s unlocked, but features like VoLTE/Wi‑Fi Calling or MMS may need correct APN settings or may vary by model.

On any Back Market product details page, open “Technical specifications” to see “Carrier compatibility”.

I already have a mobile plan/network

Filter listings by network

In the app, use the “Carrier compatibility” filter to choose locked or unlocked.

On desktop, use the left‑side “Carrier compatibility” filter to choose “locked” or “unlocked”.

Pro tip: If you already have a contract with a network, buying a phone locked to that network may cost less.

I don’t have a mobile plan/network

Check the listing for network compatibility

On the product details page, the title indicates if the phone is unlocked or locked to a network.

Near the top, you’ll see “Works with all carriers” (unlocked) or a list of supported networks (if locked).

How to activate my phone after purchase

1. Find the IMEI

To connect your phone to your chosen UK network, you’ll need its IMEI (International Mobile Equipment Identity).

• iPhone: “Settings” > “General” > “About”
• Android: “Settings” > “About phone” > “Status”
• All phones: dial *#06# and your IMEI will appear

2. Check/activate with your network

Most UK networks let you check compatibility and activate online. You may be asked to enter your IMEI, insert your SIM/eSIM, and restart your phone.

Don’t see your network?

It might be an MVNO (a brand that uses one of the major UK networks). See the list above, or visit your provider’s help pages to check device compatibility and activation steps.