Three & O2 are two of the big four operators in the UK which operate their own mobile networks. Read who comes out on top in our network comparison.
Three is offering customers unlimited data with unlimited UK minutes and texts for just £10.50 a month! The deal is a 24-month contract. There are no data or speed caps.
Three also offers 5G at no extra cost as well as access to Go Roam. Click through to ensure you don’t miss out!
Three hasn’t been around for as long as some of the other big network operators such as Vodafone and EE, however they’ve made themselves relevant through great customer offers such as ‘Go Roam’ which offers customers inclusive roaming in worldwide destinations like Australia & the USA. They’ve also become synonymous in the industry with great SIM only and phone contract deals.
O2 is one of the premium UK networks, which has become associated with quality due to consistently solid network coverage and speeds couple with the O2 priority app offering customers some of the best perks available in the UK mobile market. Recent price reductions and introduction of a great roaming scheme means O2 is offering increasingly better value.
Three Mobile’s price plans are available in 1 month, 12 month or 24 month deals and the longer the contract you commit to is, the better rates you’ll get. The mobile provider currently offers 13 SIM Only plans and they all come with unlimited minutes & text, as well as 5G at no extra cost. All plans include the ‘Go Roam’ perk as well. This feature lets you roam freely in a total of 71 destinations worldwide.
Another interesting proposition offered by Three is ‘Go Binge’ and it allows unlimited streaming on Netflix, TV Player, Soundcloud, Apple Music, Deezer & Snapchat. However, ‘Go Binge’ is only available to contract customers with 12GB or more data.
O2’s SIM Only plans are slightly pricier, but they most certainly offer great value. The network’s SIMO deals are available in 1 month, 12 month and 18 month contracts. Outside of the 30 day 500MB and 1GB plans, all O2 deals come with unlimited minutes and texts. Also, regardless of your SIMO plan all customers benefit from O2 Priority’s daily/weekly offers and over 16 thousand free Wi-Fi hotspots.
The network’s most affordable plan is priced at £10/month, but you’ll have to sign up for 18 months with O2. This plan’s data allowance is 10GB/month and it includes 6 months of Disney+ for free. The carrier offers an unlimited data plan too, but you’ll have to commit for a year or longer, as monthly rolling plans don’t include any unlimited data options.
You can click here for a more detailed review on O2’s price plans.
Three offers more valuable monthly rolling plans with great value unlimited data plans. And if you’re willing to commit to a 24 month SIMO deal, Three’s prices are competitive across the whole market.
Currently, Three is offering four different PAYG packs and these have considerably larger data allowances than most other networks. PAYG customers also get 5G at no extra cost & access to the ‘Go Roam’ proposition.
|TARIFF||Minutes & Texts||Data||Price|
If you wish, you can also use the Three Network as a traditional PAYG service, this includes data too. The table below shows Three’s current rates.
O2 proposes two different PAYG alternatives called Big Bundles and UK & International Bundles.The latter is specifically for international calls, but includes some UK minutes & texts. O2’s Big Bundles are pricier and they offer significantly less data than Three’s PAYG packs.
O2 won’t allow you to use its network as a traditional PAYG either. You’ll have to top-up every month to keep your SIM active.
Both networks offer unlimited minutes & texts with their PAYG bundles, but when it comes to data Three is well ahead of O2. Plus you’ll get 5G on Three’s PAYG deals. You may also use the Three network as a traditional PAYG deal, while this isn’t possible on O2.
O2 offers a wider range of mobile devices compared to Three. But regardless, with both Three & O2 you can find a wide range of handset options including budget friendly brands all the way to your flagship Apple releases.
Three’s deals are generally cheaper than O2’s, however, O2 offers a year long warranty for refurbished smartphones. Also with O2 you’re able to split your bill into a phone plan and an airtime plan, so upgrading your device is easier with O2. Three actually offers this too, but it isn’t as flexible as its competitor in this regard. On top of this, you get to choose the length of your contract starting from 3 months all the way up to 36 months on O2. Three offers a limited selection when it comes to contract length.
O2 offers a wider selection of mobile devices and way more flexibility than Three does. Our winner in this section is without a doubt O2.
Both Three and O2 offer over 99% population 4G coverage, and their landmass coverage seems to be around the same level. Both networks get the basics right and provide decent 3G coverage as well, however, Three doesn’t offer any 2G coverage. While it may sound unnecessary, 2G is still a good option for voice calls and text messaging in some rural locations. Even EE, the UK’s largest mobile network operator with the best 4G coverage relies on 2G when it comes to voice calls.
As for data speeds Opensignal’s April 2021 test results show Three’s average 4G download speed is tracking at 19.3Mbps and upload speed at 6.8Mbps. Meanwhile, O2’s 4G download speed was measured at 17.3Mbps and upload speed was at 6.7Mbps. They are not as fast as EE, but these speeds are enough for watching full HD videos on YouTube or streaming content, as well as many other activities.
Three’s average speeds are a bit better than O2’s, while O2’s network coverage is a little above Three’s. We’re giving the win to O2 mainly because the network also offers 2G coverage.
Three has 140MHz of usable 5G spectrum and it’s utilizing 100MHz of it to provide 5G across the country. While the available 5G spectrum is a key factor, there are others to how fast your internet speed will be. Three’s 5G network launched at the end of February 2020 and it’s active in 194 cities and towns in the UK at the moment. All Three customers enjoy 5G data speeds at no extra cost.
O2 only has 40MHz 5G spectrum and while there are no concrete test results yet, the network seems to offer the slowest data speeds out of the four major operators. The network’s 5G is live in 193 cities and towns in the UK. O2 also offers 5G at no extra cost, so if you have a 5G ready handset, make sure to ask for an O2 5G SIM to access the network’s 5G service.
As for 5G download speeds; Three 5G is averaging around 116Mbps, meanwhile O2 5G is averaging around 129Mpbs, making O2 the faster 5G network on average.
To enjoy 5G data speeds on either Three or O2, you’ll need a 5G ready handset and of course be in an area with 5G coverage.
Three 5G is available on all plans, plus the network has the better infrastructure. O2 5G is improving at a good rate, but we give the win to Three, as their 5G service is slightly better overall.
According to the most recent network tests done by umlaut (an independent testing body) O2 is ranked third while Three is at the bottom. EE is still at the top of table, with Vodafone catching up.
O2 made a huge improvement and took over Three according to both umlaut and Open Signal, but the difference isn’t that big either. In umlaut’s voice call tests the call setup times of O2 were only slightly better than Three’s.
Yet another close race and another close win for O2. The carrier made huge improvements over the last year and caught up with Three in terms of voice call quality and even passed its competitor.
4G Calling (also known as VoLTE or Super-Voice to Three customers) is a service which lets you make and receive phone calls over a 4G network. With 4G Calling the quality of your voice calls improves significantly.
Wi-Fi Calling utilises an available Wi-Fi network for you to make HD quality voice calls if you’re 2G,3G or 4G signal is weak.
Both Three and O2 offer these perks to their customers. Three customers can enjoy both 4G Calling and Wi-Fi Calling at no extra cost, even if they’re on a PAYG deal. As for O2, you’ll have to be on a pay monthly plan or else you won’t get either. With either network you’ll also need a handset which supports 4G Calling and Wi-Fi calling.
You may also want to have a look at other networks with 4G Calling and Wi-Fi Calling.
Both networks offer 4G Calling and Wi-Fi Calling to their customers, but O2 limits these features to pay monthly customers only. If you join Three, you’ll get it no matter which plan you choose, even on PAYG.
With Three, you will get free Wi-Fi on the London Underground at over 250 stations, but that’s about it. The network doesn’t really offer anything special in terms of free Wi-Fi hotspots.
However, free Wi-Fi is O2’s forte and the carrier does it right. O2 customers can automatically connect to over 16 thousand free Wi-Fi hotspots and about seven thousand of them support O2’s WiFi Extra feature, which can significantly improve your voice call quality. Once you register at one of these Wi-Fi hotspots, you’ll connect to them automatically whenever they’re available. You can use O2’s Wi-Fi Hotspot finder and register your SIM.
O2 offers significantly more free Wi-Fi hotspots than Three, so it’s a clear win for O2.
Tethering is the action of turning your mobile phone into a personal hotspot. This means you can share your mobile data with compatible devices such as other smartphones, tablets, laptops, gaming consoles etc.
Both Three and O2 allow tethering on all their plans, be it pay monthly or PAYG. However, O2 restricts tethering to a maximum of 12 devices and there’s also a fair usage policy of 650GB/month if you have an unlimited data plan. There are no restrictions or throttling if you’re on Three.
As always, we’d like to remind you that when you tether on a regular basis you may run out of data before you realise. It might be worth checking out our Unlimited Data Plans in the UK article if you’re planning to tether often.
With no restrictions or limitations to tethering, Three takes the win here. Unlimited data plans are the safest way to tether to prevent any nasty bill shocks & Three’s unlimited data plans are unrivalled.
Every mobile network operator in the UK must provide inclusive EU roaming. This means you can take your minutes, texts and data with you on your travels with both networks. However, Three’s ‘Go Roam’ is included in all deals, which means you get inclusive roaming in 71 countries.
O2 tracks behind in this area with 48 European destinations on its base plans. If you choose a premium plan, this number will increase to 75 countries though. The network will let you make calls and use data in the USA, Australia, New Zealand and 24 more other destinations with this feature but you’ll only have a daily allowance of 120 minutes, 120 texts and unlimited data with speed restrictions.
O2 also has an add-on called ‘O2 Travel’ which will keep you connected in additional destinations for £4.99 a day. The add-on resets daily, at midnight local time.
If you’re planning to make a trip soon or travel regularly outside the UK, we have a detailed roaming abroad guide to help you out!
Three’s ‘Go Roam’ is currently the best inclusive roaming scheme in the UK. O2’s ‘Travel Inclusive Zone’ feature has four more countries, but unlike ‘Go Roam’ it’s not included for both contract and PAYG customers.
Three’s ‘Go Roam’ allows customers to use their minutes, texts and data allowance in 71 destinations across the world at no extra cost. You won’t have to worry about any roaming charges. However, you should still check Three’s fair usage policy when roaming abroad.
All the contract handset & SIM only plans with 12GB of data or above will let you use unlimited data on apps like Netflix, Apple Music, Snapchat, Soundcloud, Deezer and TV Player. We’d like to remind you that Three is letting you use these apps without burning through your data, but you may still need subscriptions to use these services.
Three offers great unlimited data deals and they come in 1 month, 12 months and 24 months contracts in terms pay monthly plans. There is also an unlimited data pack for the network’s PAYG customers.
Three’s unlimited data plans come without restriction. So you won’t have to worry about a fair usage policy or speed restrictions etc.
|Tariff||Data, Minutes & Texts||PRICE|
|Three Advanced||Unlimited - 1 month||£26.00|
|Three Advanced||Unlimited - 12 months||£16.00 (Half Cooked Deal)|
|Three Advanced||Unlimited - 24 months||£10.00 6 Months - £20 from month 7|
The network is once again proving its customer friendly approach by providing 5G coverage to all members with no exceptions, and at no extra cost. There’s no other network in the UK -be it large or small- which offers 5G speeds to everyone, let alone doing it without extra charges. On top of that, Three’s pricing is quite competitive with many extra perks being included in all plans.
Three’s special offers aren’t that exciting, but existing customers can still get some discount options when they’re purchasing additional SIM plans. Most of these offers save you about £2 a month, but given how Three already proposes competitive prices, these may work out cheaper than other operators under a family/group discount.
If you’re a student or a parent to one, you might also want to check out what networks offer student discounts. Alternatively, you can head on to our best student SIM deals in the UK guide to find out more about other networks’ student deals!
O2 Priority is a deals app exclusive to O2 mobile customers and it’s probably the best & most popular feature offered by the provider. O2 priority has a mixture of exclusive offers, as well as offers ‘Open2All’. ‘Open2All’ offers are handpicked by O2 based on the best current deals available on the market. To get access to the deals offered by O2 Priority, you’ll need to download the free app from the store.
With O2’s Refresh feature, customers may change their phones whenever they want. O2 Refresh splits the bill into a device plan and an airtime plan. The phone plan is the cost of the phone you get from O2, and the airtime plan is your minutes, texts and data allowance per month. This way, O2 offers you flexibility by not locking you into a long term phone contract. Your airtime plan will continue, but you can purchase a new device on a new contract if you feel like an upgrade is due. With O2 Refresh, you can just pay off your device plan and be free to upgrade to a new one while continuing to use your selected airtime plan.
O2’s ‘Bolt Ons’ start from £3 a month and let you top-up when you’re low on minutes, texts, or data. You can also find special Bolt Ons for calling abroad, or if you’re travelling abroad yourself.
O2 now offers unlimited data plans, just like all the other major networks in the UK. However, the network sets certain restrictions. Customers may only tether up to a maximum of 12 devices and they’re allowed to use upto 650GB data per month.
You can either get a 12 or 18 month unlimited data contract, as the provider doesn’t offer unlimited data for its monthly rolling tariffs. Both deals include the ‘O2 Travel Inclusive Zone’ bolt on and 6 months Disney+.
If you want to see all the other options for limitless data deals make sure to check out Half Cooked’s Unlimited Data Plans in the UK 2020 guide.
When buying a phone from O2, the network puts you in control and lets you create a plan that suits your needs. You’re allowed to choose how much you wish to pay upfront, how much data you want to have in your plan, as well the length of your contract. You may spread the balance for up to 36 months to keep the cost down or as little as 3 months to pay it off as quickly as possible. You can also change your tariff on a monthly basis.
O2’s data rollover feature is targeted at PAYG customers. Any unused data you have will be rolled over to the next month, but you’ll have to keep the same bundle and you must also renew it on the very same day. Failing either will result in your rolled over data to reset.
You can have 20 additional plans under one main account on O2 and use this feature as a family plan. Plus the network offers up to a 40% discount. On top of that, when you bring in a family member to O2 via your referral link, both you and your family member will get a £25 Amazon voucher.
Ineligible tariffs: Business tariffs, standard tariffs, Apple Watch tariffs and any tariff that already has a discount applied.
Three offers some amazing essential perks, and 5G at no extra cost is great. We would call it a draw, or perhaps a slight win for Three, if it wasn’t for the O2 Priority App!
This is a tight one, as both networks get the basics right and offer great extras & benefits. Overall, Three’s prices are more competitive within the market, but O2 offers great flexibility when it comes to phone plans and you get great weekly deals with O2 Priority.
We’re giving the win to Three, because the network offers 5G at no extra cost to all customers while offering some of the most competitive prices in the market.
Yes, Three has 5G and it’s free to all the network’s customers, be it pay monthly or PAYG. Three’s 5G is available in 194 cities and towns. Plus the network’s 5G service is the fastest in the UK.
No, unfortunately Three doesn’t have any 2G coverage. The network relies on 3G and 4G for voice calls and texting. However, both 4G Calling and Wi-Fi Calling are available to all Three customers.
Yes, the Three Network has 4G Calling, known as Super-Voice. It’s a free scheme available to all Three customers.
Yes, Three offers Wi-Fi Calling to all its customers and it’s free of charge. As long your device supports it, you’ll benefit from this scheme.
Sadly, Three doesn’t offer any data rollover scheme. Three is the only major network in the UK without a data rollover feature.
Yes, Three does have an app and it’s quite useful to view your bills, check your allowances and sort your upgrades and so on. You can also connect to a live customer service representative.
Three claims they offer the fastest 5G data speeds in the UK, but this isn’t proven yet. We are waiting for the test results from independent bodies to see if these claims are indeed true. However, it’s true that currently Three has the largest amount of 5G frequency spectrum of any of the UK’s mobile operators.
You can use Three’s inclusive roaming (commonly known as ‘Go Roam’) in 71 different destinations across the world.
Yes, O2 launched its 5G service in October 2019. Currently the network offers 5G data speeds in 193 cities and towns.
Yes, O2 provides Wi-Fi Calling, but only to pay monthly customers. You’ll also need a compatible device for the feature to work properly.
Yes, O2 offers a 4G Calling service, however this is only available to pay monthly customers. You’ll also need a compatible device in order to use the feature.
Yes, O2 Priority App is free for everyone and it’s free to use.
If you recently joined O2, that might be the reason. If this is not the case the Priority App might be experiencing some issues. If the problem continues please make sure to contact O2’s customer support.
Transferring a phone number from one network to another shouldn’t take any longer than 24 hours in the UK. You should be able to make phone calls within a couple hours, but texting might take longer. If it takes longer than a day, contact your new network’s customer service.
Open Signal’s April 2021 reports state that O2 has the slowest 4G data speeds in the country. The operator’s average 4G download speed is measured at 17.3Mbps and average upload speed is at 6.7Mbps.