Poor mobile signal at home is usually down to one of three things: your building, your network's coverage at your address, or your phone. The good news is that several of the fixes are free and take a few minutes. Work through those first, then move on to switching network, adding a second SIM or fitting equipment.
This guide covers eight fixes that work in the UK, which ones suit which situation, and what the rules are on signal boosters. It was researched on 15 Oct 2026 using Ofcom's published guidance.
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Step outside and check your bars. If signal is good outside but poor indoors, the walls are the problem: turn on Wi-Fi calling and, if you need more, ask about a femtocell or fit a legal repeater. If signal is poor outside too, the network is the problem: check coverage at your postcode and switch, keeping your number.
Best next step: run your postcode through Ofcom's coverage checker before you spend anything.
1. Start with the phone itself
If other people on the same network get signal in the same room and you do not, the phone is the first suspect. These checks cost nothing:
- →Restart the phone. It forces a fresh search for the strongest nearby mast.
- →Turn airplane mode on for ten seconds, then off again. This has a similar effect without a full restart.
- →Install any software update. Updates can include changes to how the phone works with your network.
- →Take the SIM out, check it for damage and put it back. If it is old or damaged, ask your network for a replacement.
- →Remove a thick or metal case and test again.
- →Check your network settings: make sure network selection is set to automatic and that 4G or 5G is switched on if your plan includes it.
2. Turn on Wi-Fi calling
If you have home broadband, Wi-Fi calling is the quickest real fix. Your phone makes and receives calls over your Wi-Fi when mobile signal is weak, using your normal number and the normal phone app. No extra app is needed.
According to Ofcom, calls are typically included in your normal minutes allowance, and out-of-plan calls are charged at the standard rate. Ofcom also notes the limits: not every handset or package supports it, you may need to ask your network to activate it, and you should check with your network whether texts work over Wi-Fi too.
To turn it on, look in your phone's settings under Phone, Connections or Mobile network for a Wi-Fi calling switch. If you cannot find it, your network or handset may not support it on your plan, so ask your network.
3. Check coverage at your postcode
Before you change anything that costs money, find out how each network is predicted to perform at your address. Ofcom's coverage checker shows 4G and 5G coverage from each network for your postcode, and each network has its own checker too.
Look at indoor predictions, not just outdoor ones, because that is where you are having trouble. Treat every result as a prediction rather than a guarantee, and ask neighbours which network works inside their homes. Budget SIM brands use the same masts as EE, O2, Vodafone or Three, so check the host network. Our guide to what an MVNO is explains how that works, and EE vs O2 vs Vodafone vs Three compares the four networks.
4. Switch network and keep your number
If another network is clearly stronger where you live, switching is often the cheapest permanent fix. Text PAC to 65075 from your current phone to get your PAC code, give it to your new network, and your number moves across. Our PAC code guide walks through each step, including what to check if you are still in a contract.
Not sure the new network will actually work indoors? Test it first on a 30-day SIM. If the signal at home is good after a few weeks, move your number across. If not, you have only paid for a month. You can also start from a network page such as EE, O2, Vodafone or Three.
5. Add a second network with dual SIM
If you are happy with your current plan but one network is weak in part of your home, you do not have to choose. Many phones can hold two SIMs at once, often one physical SIM and one eSIM. Keep your main plan and add a cheap SIM-only plan or eSIM on a different host network, so your phone has a second set of masts to use.
Check that your phone supports dual SIM and is unlocked before you buy. A low-data plan is usually enough for a backup, so look at SIM-only deals under £10 or a rolling 30-day plan you can drop if you no longer need it.
6. Use a backup eSIM: the Honest Mobile Smart SIM
A different take on the second-SIM idea is a backup eSIM built for when signal drops. Honest Mobile's Smart SIM is a data-only eSIM that works alongside your main SIM. Honest Mobile says it gives you 500+ apps on EE, O2, Three and Vodafone, including WhatsApp, and that you can switch to it in a few taps or let it kick in when your main SIM loses signal.
At the time of writing (15 Oct 2026), Honest Mobile listed it at £45 a year (which it says works out at £3.75 a month) or £10 a month on a rolling plan, with a 14-day money-back guarantee. Check the current price before you buy.
Know the limits before you buy:
- →It is data only, for a set list of apps. Honest Mobile says you need your main SIM for normal calls and texts, social media, streaming and open web browsing.
- →You can make WhatsApp calls and send WhatsApp messages over it, but not ordinary phone calls or texts.
- →It is eSIM only. Check your phone supports eSIM alongside your main SIM before you buy.
- →Honest Mobile says it does not support VPNs at the moment.
If you already use two SIMs, note that Honest Mobile's Smart SIM FAQs say most phones support a maximum of two active SIMs at once, so you may need to turn one off to add it.
It suits you if your signal at home is patchy rather than absent, and what you mostly miss is messaging apps such as WhatsApp when it drops. It will not fix missed ordinary calls at home; Wi-Fi calling or a better network does that. It is one option among several, not a replacement for getting the right main network.
7. Fit a legal signal booster (repeater)
A repeater, often sold as a signal booster, picks up the signal outside your home and rebroadcasts it indoors. It works best when there is a good outdoor signal to boost, typically with the unit near a window or upstairs. It will not create signal where there is none.
Be careful what you buy. In May 2022 Ofcom extended the range of static indoor repeaters people can buy and install themselves without a licence, including ones that boost more than one network, provided they meet its technical requirements. Repeaters that do not meet those requirements remain illegal, and Ofcom warns that adverts for illegal devices often claim to be approved.
Ofcom publishes a list of repeaters it understands meet its requirements on the same page. Check any model against that list before buying, and buy from a reputable retailer. Ofcom notes that some installations, especially where the outdoor signal is very weak and an external antenna is needed, may need a professional.
8. Ask your network about a femtocell
A femtocell (sometimes called a signal box) is a small unit that connects to your network through your home broadband and acts like a mini mast inside your home. It usually plugs into a power socket and into your router with a cable.
Ofcom says femtocells can be a good solution if you have good broadband but poor indoor signal, that some providers offer them, and that some charge for them. It only boosts the network that supplied it, so ask your network directly whether it still offers one and on what terms.
Which fix suits you
Start by checking your signal just outside your front door, then find your situation below.
| Your situation | Try first |
|---|---|
| Good signal outside, poor indoors, decent broadband | Wi-Fi calling, then ask your network about a femtocell |
| Good signal outside, poor indoors, weak or no broadband | An Ofcom-compliant repeater placed where the outdoor signal reaches |
| Poor signal outside as well | Check coverage at your postcode and switch network, keeping your number |
| Your network is poor but others work in your home | A 30-day SIM on a better network, or a second SIM on that network |
| Signal is mostly fine but drops out at times | Wi-Fi calling plus a backup eSIM or a second SIM for essential apps |
| Only your phone struggles; others on the same network are fine | Restart, update, reseat the SIM, then ask your network to check it |
Found a network that works at your address?
Compare SIM-only deals on that network, including budget brands that use the same masts, and check contract length and any mid-contract price rise before you switch.
Compare live SIM-only deals →What this is not
It is not a coverage guarantee. Coverage checkers give predictions, and real indoor signal depends on your building and where you stand in it. We do not sell repeaters or femtocells, and we do not recommend specific repeater models; Ofcom's list is the place to check. Prices and product details were checked on 15 Oct 2026 and can change.
Frequently asked questions
Why do I have no signal on my phone at home?
Usually it is one of three things: the building, your network's coverage at your address, or the phone. Ofcom notes that thick stone walls, slate roofs, modern glazing and insulation can all weaken indoor signal. If you get good signal outside but not indoors, the building is the likely cause. If you get no signal outside either, check your network's coverage at your postcode. If other phones on the same network work in the same room, restart yours, check for software updates and reseat the SIM.
Does Wi-Fi calling cost extra?
Ofcom says calls made with Wi-Fi calling are typically included in your normal minutes allowance, and calls outside your allowance are charged at the standard rate. It uses your broadband, so it does not use your mobile data. Your network and your handset both need to support it, and you may need to ask your network to switch it on.
Are mobile signal boosters legal in the UK?
Only some. Since May 2022, Ofcom has allowed people to buy and install certain static indoor repeaters without a licence, including ones that boost more than one network, as long as they meet Ofcom's technical requirements. Repeaters that do not meet those requirements remain illegal. Ofcom publishes a list of repeaters it understands meet the rules, and a repeater only helps if there is a usable signal outside to boost.
Which network has the best signal where I live?
There is no single answer, because coverage varies street by street. Enter your postcode in Ofcom's coverage checker and in each network's own checker, and look at indoor predictions, not just outdoor ones. Remember that budget brands use the same masts as EE, O2, Vodafone or Three, so check the host network. Predictions are not guarantees, so ask neighbours which network works for them.
Can I keep my number if I switch network for better signal?
Yes. Text PAC to 65075 from your current phone to get your PAC code, give it to your new network, and your number moves across. If you are still in a contract, check for early termination charges first. A 30-day SIM on the new network is a low-risk way to test the signal at home before you commit.
What is a backup eSIM and do I need dual SIM?
A backup eSIM is a second, digital SIM that sits alongside your main one so you have another route online when your main network drops out. One example is the Honest Mobile Smart SIM, a data-only eSIM for a set list of apps (at the time of writing, 15 Oct 2026, from £45 a year or £10 a month). Check your phone supports eSIM alongside your main SIM before you buy. It does not replace your main SIM for normal calls and texts.
Do networks still give out femtocells or signal boxes?
Some do. Ofcom says some mobile providers offer femtocells to customers who struggle to get a good indoor signal, and that some providers charge for them. A femtocell plugs into your broadband router and acts as a small mast for your network inside your home. Ask your network directly whether it still offers one and what it costs.
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