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Best UK Mobile Networks For Indoor Coverage

Different mobile networks can offer better or worse coverage dependent on your location and whether you are outdoors or indoors. In this article, we’ll help you find out which mobile provider may be the best for your home or office.


It can be difficult to get a good mobile signal indoors, especially if you’re living in an area where your provider offers poor network coverage. Getting good coverage from a mobile network operator at indoor locations such as homes and offices is still a major issue. If we could highlight one UK mobile network offering the best indoor coverage, we would, but unfortunately that’s not the case.

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On paper, low frequency signals have a better chance to penetrate obstacles like walls and ceilings. That would make O2 & Vodafone better than other providers as their 3G/2G signals are on a low 900Mhz frequency, meanwhile EE and Three are operating at much higher frequencies. However, in practice whichever network’s’ transmitter is closer to your location will determine the better indoor coverage. On top of that, even the layout of your house can be a deciding factor on which network’s signal will be stronger.

There are also two great features you can benefit from to improve your indoor coverage, provided your mobile network operator offers them with your price plan. These features are dubbed as 4G Calling (or VoLTE) and Wi-Fi Calling, and they will both help you stay connected. You can also use a mobile signal repeater to improve coverage at your location, but if your device supports Wi-Fi Calling, you really don’t need to invest in this device.

This article will be covering how the most popular UK mobile networks perform indoors and what 4G Calling & Wi-Fi Calling are. We will explain how you can get these two voice call quality improving features with each mobile network and the benefits in doing so.

We briefly mentioned 4G Calling and Wi-Fi Calling earlier, but we think a proper explanation is needed in order to understand why these two features are great to have and how they add great value to your plans. Keep in mind that these two features are not available on all mobile networks and some carriers only offer these with their premium SIM plans. On top of that, your handset must support 4G Calling and Wi-Fi Calling too.

What is 4G Calling (VoLTE)?

When it first launched, 4G was only used for data, but nowadays almost all modern smartphones have 4G Calling, which allows you to make calls over your carrier’s 4G network and it eliminates most indoor blackspots. This also means you can also make the most of 4G data speeds while you’re on a call, plus if the other party also has 4G Calling and it’s enabled, your calls will be much clearer.

4G Calling is a must have, if you want to improve your network coverage indoors. We would recommend checking out Three, because 4G Super-Voice (their fancy name for 4G Calling/VoLTE) is one of the better 4G calling options and it’s available to all Three customers. Even their traditional pay as you go customers can enjoy this feature at no extra cost.

What is Wi-Fi Calling?

Wi-Fi Calling lets you make and receive calls and send messages over a Wi-Fi network, even when you don’t have any standard mobile signals available. Normally, there are no additional charges to Wi-Fi Calling, however, some networks only offer this feature with their premium contracts. For example, Wi-Fi Calling is already included in your service plan if you’re a Three or SMARTY customer, but EE or Vodafone customers would have to opt for their providers’ pay monthly SIM plans (except Vodafone Basics plans) in order to benefit from this feature.


What is a Mobile Signal Repeater?

A mobile signal booster (also known as mobile signal repeater) is a type of bi-directional amplifier used to improve reception. Not so long ago, almost all the mobile networks were offering these devices to improve indoor coverage and eliminate blackspots. Mobile signal repeaters work just fine, but the level of improvement still depends on how good the network coverage is in your area. Unfortunately, they cannot magically create new mobile signals!

Usually they do their job just fine, but they’re not needed as much anymore. Especially since Wi-Fi Calling is becoming more and more popular. Even a smaller carrier like SMARTY offers Wi-Fi Calling nowadays. If you have decent Wi-Fi at home and a Wi-Fi Calling enabled handset, we think it’s pointless to invest in a gadget like this.

We can only recommend getting a cellular booster, if your reception is really bad at your location. Just know that good ones are usually expensive, and the cheap ones might not meet your expectations.

Best UK Networks for Indoor Coverage

As we stated earlier, there isn’t just one best network for indoor coverage. Having said that, we can still predict which mobile networks are better for indoors based on Ofcom’s coverage checker. At the end of the day, you will still get the best indoor coverage from whichever network has a transmitter closer to your house or office.

We’d also like to point out that all four major mobile network operators in the UK offer over 99% 3G coverage, so our main focus will be 4G coverage and if these networks offer 4G Calling and Wi-Fi Calling.


The UK’s largest mobile network operator’s 4G infrastructure is unrivalled. EE has the most 4G coverage, and the fastest 4G data speeds in the country. On paper, you should get better indoor coverage from other networks like O2 and Vodafone, but EE has more telecommunications towers thanks to its parent network BT.

The network’s 4G geographical coverage is above 95% and it’s still increasing. EE also offers 4G Calling and Wi-Fi Calling at no extra cost to their pay monthly customers. This means you can stay connected pretty much anywhere in the UK, as long as your device supports 4G Calling and you’re in an area with EE’s 4G network.

Unfortunately, these two features aren’t available to EE Flex and EE PAYG customers. Make sure to check out our EE Review to discover more about their coverage and SIM only offers.


Being the oldest network operator in the UK, Vodafone also is a reliable choice if you wish to get decent indoor coverage. The network’s 4G geographical coverage is over 90% and it’s growing. Plus both Wi-Fi and 4G Calling are available on Vodafone RED and Vodafone Unlimited plans. The only exceptions are Basics plans and Vodafone’s PAYG big bundles.

Vodafone’s calls are transmitted over low frequency on 3G and 2G, so their signals have a better chance to penetrate your walls and other obstacles to reach your phone.

You can read our Vodafone Review to learn more about the carrier, especially if you’re roaming abroad on a regular basis.


While O2’s 4G coverage is slightly behind Vodafone, we think the network is pretty much on par with them. On top of that, O2 also operates over low frequency on 3G and 2G. In fact, all O2 pay monthly customers can benefit from both VoLTE and Wi-Fi Calling, provided their phones support these different features. O2 PAYG customers don’t get these features, but this might change in the near future according to the network’s official support page.

O2 customers also benefit from O2 Wi-Fi as well. Whenever they’re in an O2 Wi-Fi hotspot, their devices automatically connect and their calls are made over this service. O2 claims their free Wi-Fi service allows their customers to make higher definition calls. O2’s free Wi-Fi hotspots can be found in many indoor locations.

O2’s custom plans are a massive selling point, as they allow customers to build exactly what they want out of their mobile contract, our O2 Review provides a great insight into how these custom plans work.


Out of the four major operators in the UK, Three is the least ideal network when it comes to staying connected indoors. The network doesn’t have 2G, which is still a reliable fallback option, and on top of that, their 4G coverage is significantly behind EE, Vodafone and O2. Moreover, calls made over Three’s network are transmitted over high frequency, meaning there’s less chance for the network’s cellular signals to pass through walls and other obstacles.

Of course, we aren’t saying you should completely ignore Three. We can’t stress this enough, whichever network has a transmitter closer to your location will offer the better indoor coverage.

Three does however offer 4G Super-Voice and Wi-Fi Calling at no extra cost and they’re available to all customers. You also get Three Go Roam on all mobile deals, including the network’s traditional pay as you go service.

Three also has the fastest 5G download speeds and the most 5G coverage in the UK. The best part is, all Three SIMs are 5G enabled and there are no extra charges. They are most certainly offering some of the best 5G SIM only plans in the UK and you can learn more by reading our Three Review.

BT Mobile

Piggybacking on the EE Network, BT Mobile offers the very same network coverage on all fronts. Their customers also get Wi-Fi Calling & 4G Calling at no additional charge. The network doesn’t offer any contract-free plans, so you can’t just order a free SIM and test their coverage first. However, you can get a free EE SIM and test it once your SIM arrives.

If you’re looking for a family mobile plan, we strongly recommend checking out BT Mobile. Alternatively, you can also read our BT Mobile Review and discover more even about their SIM and phone deals.

Sky Mobile

Powered by O2, Sky Mobile offers decent indoor coverage and their coverage is strengthened by free 4G Calling & Wi-Fi Calling. Sky Mobile doesn’t have a PAYG service or commitment-free SIM only deals, which means you must undergo a credit check first to join their network.

If you’re an existing Sky Mobile customer, you can grab some extras and discounts too. The network also offers one of the best data rollover schemes in the UK by a long way. You can save your unused data in your Sky Piggybank for up to three years, our Sky Mobile Review dives into the many great features Sky Mobile offers.

iD Mobile

Whilst being powered by Three is a bit of a handicap in terms of indoor coverage, it would be unfair to leave iD Mobile out given how the network offers both 4G Calling and Wi-Fi Calling to their pay monthly customers.

Keep in mind that iD Mobile’s 30 day SIM deals are still contracts, meaning you’ll have to pass their credit check in order to get these two features. The network also offers pay as you go bundles for light data users, but they don’t include neither 4G Calling nor Wi-Fi Calling. See our iD Mobile Review and find out more about their SIM only plans.

Virgin Mobile

Virgin Mobile is currently piggybacking on EE’s network, but they will merge with O2 in the near future. Either way, Virgin will deliver good network coverage indoors. However, Virgin Mobile doesn’t offer 4G Calling, you only get Wi-Fi Calling at the moment. It still puts them ahead of most other MVNOs (mobile virtual networks).

The network usually offers great discounts to both newcomers and existing customers, however, their unlimited data plans are only available to existing Virgin Broadband and TV customers.


We love SMARTY’s SIM only plans for two reasons. The network offers money back on selected plans, and you get large amounts of data at competitive prices. In fact, SMARTY’s unlimited data plan is usually the cheapest on the market.

The carrier is also one of the latest MVNOs to offer Wi-Fi Calling at no extra cost, so we decided to add them to our list. SMARTY aims to launch their 5G service soon, but as of yet, there isn’t a date set in stone. Our SMARTY Review details all the great benefits of signing up to SMARTY.

Half Cooked’s Overall Breakdown

If your handset supports 4G Calling and Wi-Fi Calling, you can’t go wrong with any of the networks we listed above. Due to having superior 4G coverage EE tops the list, but remember, not all EE plans come with these features and their prices are usually quite expensive. On the other hand Three offers both features at no extra cost, even if you’re only using the network’s PAYG service, but their general indoor coverage isn’t on par with EE.

If your device is older, or doesn’t support 4G Calling & Wi-Fi Calling, we strongly recommend picking the network that has a transmitter in your area. If all networks offer similar coverage in your area, then O2 or Vodafone will provide better indoor coverage. You can also choose one of their MVNOs, the coverage should be identical.


Are mobile signal boosters good?

Yes, they are actually not bad, but given how most modern handsets support Wi-Fi Calling, and how expensive these boosters can be, we don’t think they’re worth it. We can only recommend getting a mobile signal repeater if coverage in your home/office/basement etc. is extremely bad.

Can I make voice calls over 5G? Is 5G Calling a thing?

VoLTE supports 5G LTE devices and allows 5G users to make voice calls. We are yet to confirm 5G Calling is a thing in the UK though. It most likely needs more time.

How do I know if my phone has 4G Calling or Wi-Fi Calling?

You can check your manufacturer’s official website and find your device there. Manufacturers usually go into detail and explain what their handsets are capable of.

How do I know if my 4G Calling or Wi-Fi Calling are enabled?

It depends from device to device, and network to network. Look for an icon on top of your screen. Both features have easily identifiable little icons right next to the name of your operator or your clock.

Which network has the best Wi-Fi Calling?

Wi-Fi Calling’s quality depends on your Wi-Fi. All UK mobile networks offer pretty much identical Wi-Fi Calling quality.