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Mobile phones and SIM deals

Mobile network coverage checker

Coverage decides whether a cheap SIM is actually usable, and the only honest answers are on the networks' own checkers. Type your postcode once here, copy it into each checker below, and compare the same place on every network rather than trusting one provider's map.

Check the signal where you actually need it

Coverage is predicted, not guaranteed, and each network publishes its own figures. Type your postcode once, copy it, then paste it into each checker below so you are comparing the same place every time. Your postcode stays in this page and is never sent anywhere.

Predicted coverage is not the same as the signal in your home. Walls, roofs and windows make more difference than the map suggests, so check whether the checker is showing indoor or outdoor coverage, and ask someone who lives nearby what they actually get before you sign a contract.

Ofcom's Map Your Mobile covers all four main networks at once and also shows which operator performs best in your postal district. A brand with no checker of its own runs on one of the four main networks, so use that network's checker.

How to read a coverage map

Checkers show predicted signal, usually outdoors, and the difference between indoor and outdoor coverage is the biggest thing people miss. A postcode can be covered for 4G outside while the phone inside your house falls back to a weaker signal or drops calls. Where the checker offers both, look at the indoor figure.

Look at which technology is available rather than just whether the area is covered. 5G is not everywhere, and some checkers mark a street as covered when only the older 4G service reaches it. If the network also lists a 2G fallback, that matters for calls in a thick-walled building, and some networks are switching their 3G service off.

Predicted coverage is a best-case estimate. Terrain, walls, roofing and trees all reduce it, and a network's own map is not an independent test. Ofcom's Map Your Mobile covers all four main networks together and also shows which operator performs best in your postal district, so it is worth checking alongside the individual maps.

Cheaper brands and which network they use

Many of the cheapest UK SIM brands run on one of the four main networks, so their coverage is that network's coverage. Tesco Mobile, giffgaff, Sky Mobile and Virgin Mobile use O2; ASDA Mobile, Lebara, Talkmobile and VOXI use Vodafone; SMARTY and iD Mobile use Three. That is why no separate checker is listed for them here — use the checker for the network they run on, shown against each brand above.

Check the real thing before you commit

Ask someone who lives nearby which network they use and whether calls drop indoors. Better still, borrow a SIM from that network for a day, or buy a cheap pay-as-you-go SIM and try it in your own home before signing a 24-month contract. If you are moving to a new area, check the signal at home, at work and on the route you travel, not just at one postcode.

Coverage information comes from each network's own checker and from Ofcom's Map Your Mobile. Contract and roaming rules follow Ofcom's guidance for phone customers. CompareDirect does not sell phones, SIMs or contracts, and takes no commission from the buyers listed here.

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