O2 Review 2021: Get discounts, offers and free prize draws with O2’s priority awards scheme!

O2 is one of the big four Mobile Network Operators and has 99% 4G coverage across the UK. Read on below to get Half Cooked’s full O2 Review.

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O2 April 2021 SIM Only Offer

Latest Offer: 100GB of data with Disney + for £20!

O2 are offering 100GB of data bundled with 6 months free Disney + for just £20/month with a 12-month contract. The plan also includes unlimited UK minutes & texts.

Alongside, 5G coverage in certain locations, customers can also choose a premium subscription such as Disney+ and Amazon Prime Video to access free of charge. This deal will end soon, so hurry up!

O2-LogoIn this article, we will be reviewing O2, the second oldest mobile network operator in the UK, launching way back in 1985 under the name of Cellnet. The network rebranded as O2 in 2001 and has been operating under the same name since then. With over 34 million customers, O2 is the second-largest UK mobile network operator, behind only EE.

The mobile network offers pay monthly deals, as well as PAYG alternatives. O2 provides 5G services to its customers, just like all the other major networks. The carrier’s most unique offer is allowing you to build your own custom plan when buying a handset from the O2 Store. You may choose how much you wish to pay upfront, the length of contract (from 3 months to 36 months) and the amount of data you’ll have in your price plan. O2 Priority App also deserves a shout-out as it’s an unmatched entertainment service.


  • O2 Priority app can save you £ every week with great offers.
  • A decent range of handset options.
  • Over 16 thousand Wi-Fi hotspots.
  • Build your own plan when buying a handset.
  • Decent 5G data speeds.


  • Most tariffs are pricier than competitors.
  • The slowest 4G internet speeds.
  • Not as good 4G coverage as some of its competitiors.

Table of Contents

O2 Plans & Pricing

o2-sim-only-dealsSome networks in the UK standout with their budget friendly price plans, but O2 isn’t one of them. The carrier proposes only one type of SIM Only deal, but they do offer some flexibility when it comes to the term of a contract: 1 month, 12 months and 18 months. All O2 SIM Only deals include unlimited minutes and texts with the exception of 500MB and 1GB data plans if you select a 30 day contract. All O2 customers benefit from daily offers with Priority and O2’s thousands of free Wi-Fi hotspots.

Currently the cheapest O2 plan is priced at £10/month, locking you in for 18 months. While your data allowance is 5GB on this deal, you get 6 months of Disney+ which adds more value to your plan. O2 doesn’t offer any unlimited data plans unless you sign up for a longer term commitment. 50GB is the largest data bundle available on a 30 day SIM plan.

Some deals include extra roaming destinations at no extra cost, increasing the number to a total of 100 destinations, including popular destinations such as the USA.

Overall, O2 are slightly pricier, however they back it up with daily priority offers such as free coffees and discounted meal deals & 6 months of Disney+. Another premium network is EE, which offers great coverage and internet speeds for 4G & 5G offering unique ‘Swappable Benefits’.

If you are interested in wallet friendlier alternatives, we also recommend you check Three’s SIM Only deals. You may want to read our O2 vs EE or O2 vs Three reviews before making your final decision on which network to join. 


At the moment there are two types of Pay As You Go options, if you wish to be on O2’s network. These are called Big Bundles and UK & International Bundles. PAYG deals work on a prepaid basis, meaning you don’t have to pass a credit check to join O2.

Big Bundles

There are five ‘O2 Big Bundles’ to choose from. All ‘Big Bundles’ include unlimited minutes and texts and all your unused data rolls over to the following month. The cheapest bundle is priced at £5, but doesn’t offer any data, meaning you won’t be able to access the internet. You will, however, need to top up at least £10, but as a new PAYG customer O2 will reward you with £10 free credit!

O2 Big BundleUnlimitedUnlimitedNo Data£5
O2 Big BundleUnlimitedUnlimited3GB£10
O2 Big BundleUnlimitedUnlimited6GB£15
O2 Big BundleUnlimitedUnlimited10GB£20
O2 Big BundleUnlimitedUnlimited20GB£30

None of the ‘O2 Big Bundles’ offer unlimited data allowance. The maximum amount of data you can get is 20GB priced at £30. However, you will still have access to O2 Priority offers with all the PAYG options.

UK & International Bundles

As the name suggests, these are SIM only plans for making international calls. You can get inclusive minutes to over 40 destinations from 1p a minute on O2’s UK & International Bundles.

O2 UK & Int.25050002GB*£10
O2 UK & Int.50050005GB*£15
O2 UK & Int.1000500010GB£20
* There’s currently a special deal for both 2GB and 5GB bundles. Buying one of these, you’ll get 5x more data for up to three months. This deal will end on July 1st.

Traditional Pay As You Go

O2’s traditional PAYG service is quite lenient. If you don’t top-up, or add a Bolt On at least once in any six month period, O2 will disconnect your mobile and all of your credit in that account will be deleted. 

Alternatively, you can also check what giffgaff offers. giffgaff is a sub-brand of O2 and it’s offering flexible deals as well as good rates for light mobile data users who wish to be on a commitment-free PAYG service.

Pay Monthly Phones

o2-phone-dealsO2 has a wide range of mobile devices for you to choose from, even some refurbished ones. If you are looking to get a pay monthly phone deal you can purchase devices from the top tier manufacturers such as Apple, Samsung, Huawei and Sony. If you wish to pick a handset combined with a PAYG deal, you’ll find more budget friendly options such as Alcatel, Nokia and ZTE.

The mobile network provides a 12 month long warranty if you buy a refurbished phone. While this is nice, it can’t compete with EE’s ‘Service Pack’, which is offering a lifetime guarantee for any device you get from EE’s store, including refurbished ones and at no extra cost.

Network Coverage & Speeds

2G, 3G and 4G Coverage

o2-coverage-mapThere are currently four major mobile network operators in the UK and O2 is one of the four, in fact the second oldest after Vodafone, the other two being EE & Three. All the other networks in the UK you hear about are MVNOs (mobile virtual network operators) and they piggyback off these major networks to provide service.

O2’s 2G, 3G and 4G population coverage is over 99%, but when it comes to landmass coverage the network falls behind, taking the third place among the big four.

According to Opensignal’s April 2021 report, O2’s 4G download and upload speeds track behind the other networks. The network’s average download speed is measured at 17.3Mbps and upload speed is at 6.7Mbps.

Before you order a SIM or a mobile device from O2, we strongly recommend you check out the network’s coverage in your area. Even though the mobile network operators offer quite good coverage nowadays, your frequent areas might be in their blind spots.

Check out Half Cooked’s 4G Networks in the UK – 2021 Edition article to find out more about how other networks perform and what they offer to their customers.

5G Coverage

o2-5gO2’s 5G kicked off back in October 2019 and it has been improving since then. At the moment there are 193 cities and towns with O2’s 5G services, meanwhile EE’s 5G covers 160 cities and towns. Three’s 5G network includes 194 locations, while Vodafone also provides 5G services in 100 locations in the UK and also in 193 other places in the EU across Germany, Spain, Italy and Ireland.

Per Opensignal’s April 2021 speed test results; O2’s 5G download speeds average around 129Mpbs and their 5G upload speeds are around 10Mbps.

To get 5G from O2 you’ll need a 5G phone, a 5G SIM card and also be in a 5G coverage area.

Voice Call Quality

o2 voice call qualityIn the most recent network tests done by umlaut (an independent testing body, widely accepted as authoritative and objective) O2 ranked in third place with a score of ‘satisfactory’, just a bit ahead of Three, but behind EE and Vodafone.

Open Signal’s April 2021 tests also show O2 in front of Three, when it comes to voice call experience, but still behind the other two major networks. In umlaut’s voice call tests the call setup times of O2 were considerably longer than of EE and Vodafone, and slightly better than Three’s. However, these results also show us O2 is improving and even catching up with the others.

Wi-Fi Calling & 4G Calling

o2 4g callingWiFi Calling allows you to make calls even when you don’t have a signal, and thanks to 4G Calling gets you clearer calls and better indoor coverage. With WiFi and 4G Calling combined you can move seamlessly between WiFi and 4G network coverage to continue your calls.

O2 offers these voice call quality improving perks to pay monthly customers and at no extra cost. However, your phone needs to be compatible for 4G Calling and Wi-Fi Calling to work and Android handsets might run into some problems if they are not directly purchased from O2.

Currently O2’s 4G Calling and Wi-Fi Calling are supported by the devices below.

  • iPhone 11, 11 Pro, 11Pro Max, iPhone Xs, iPhone Xs Max, iPhone X, iPhone Xr, iPhone 8 Plus, 8, 7 Plus, 7, 6s Plus, 6s, 6 Plus, 6, SE
  • Samsung Galaxy A51, A71, S10 Lite, Galaxy Z Flip, S20, S20 Plus, S20 Ultra, S10 5G, Note10, Note10 Plus 5G, S10, S10e, S10 Plus, S9, S9 Plus, S8, S8 Plus, Note8, S7*, S7 edge* and J3 2017*, A10, A20e, A50, A70, A8, A3 2017, A6, J6, J5 (2017), A5 (2017), Note9, A7, J6+, J4+, A9, A90 5G, A40, Xcover 4S
  • Sony Xperia XZ2, Xperia XZ3, XZ2 Compact, XZ Premium*, Xperia XA2, Xperia XZ1*, Xperia XZ1 Compact*, Xperia 10, Xperia L3, Xperia 5, Xperia 1
  • Oneplus 5, 5T, 6, 6T
  • HTC U11*
  • Doro 8035*
  • Google Pixel 3, Pixel 3 XL
  • Xiaomi Mi MIX 3 5G
  • OPPO Reno 5G
  • Huawei Mate 20 X 5G, P20 and P20 Pro

Wi-Fi Hotspots

o2-wifi-hotspotsYou can get online for free on O2 with over 16,000 O2 Wi-Fi hotspots across the UK. To be able to use the hotspots you’ll need to register at one of O2’s hotspots first. You can use O2’s Wi-Fi Hotspot finder to locate the closest one to you. The network also claims the data speeds it offers is up to 10 times faster than a normal mobile connection.

Once registered, your device will always automatically connect to O2 Wi-Fi hotspots seamlessly, but you are also given the option to connect manually if you wish. Although this hotspot network belongs to O2, it’s actually free to everyone, regardless of who your mobile contract is with.

The real deal for O2 customers is the “O2 Wi-Fi Extra” feature, which allows your mobile device to seamlessly connect to O2’s Wi-Fi service at over 7,000 hotspots.The network will automatically connect you to Wi-Fi Extra when the service is stronger than the mobile network signal you receive.

While O2 offers many Wi-Fi hotspots in the UK, when it comes to this feature the top spot belongs to BT Mobile. If you want to know more about networks which offer hotspots in the UK, we’d recommend you to read our Free Wi-Fi Hotspots guide.


o2-tetheringTethering means turning your smartphone into a personal hotspot. By turning tethering on, you allow other compatible devices to share your handset’s internet connection.

You can tether on all O2 plans including pay as you go deals, but there is a limit to how many devices can connect to your personal hotspot. You are allowed to tether to 12 other devices (tablets, laptops, other smartphones etc.) at max. O2 also limits your data sharing with a fair usage limit of 650GB. If you regularly pass beyond this limit, the network might consider you a business and has the right to change your plan accordingly.

There’s also a limit to how much you can tether when you’re roaming. Within Europe, the roaming data limit is 20GB, if you exceed the data limit you’ll be charged 0.4p/MB.

At Half Cooked, we believe the best tethering deals are offered by the Three Network. Three’s deals come without any restrictions, plus you get 71 inclusive roaming destinations at no extra cost.

International Roaming

o2-inclusive-roamingWhen you’re travelling within O2’s Europe Zone as a pay monthly customer, your data allowances, minutes & texts will work just like they would in the UK. O2’s Europe Zone includes 48 destinations.

If you are travelling outside of O2’s Europe Zone, you may still be covered. ‘O2 Travel Inclusive Zone’ is included in some of the more expensive tariffs and it will increase the number of inclusive roaming countries to a total of 75. The Inclusive Zone adds USA, Australia, New Zealand and 24 more destinations to the list, where you get a daily allowance of 120 minutes, 120 texts and data.

If you’re not eligible for the Inclusive Zone Bolt On, O2 proposes another one called O2 Travel, which will keep you connected in Turkey and many other selected destinations for £4.99 a day. If you are using the O2 Travel Bolt On ,keep in mind that your allowance will reset every day at midnight local time, and your unused minutes & texts won’t be rolled over.

O2’s Europe Zone for pay as you go customers includes five less destinations, but PAYG allowances and charges will work just like they do in the UK.

If you want to discover more about international roaming deals, we have a detailed roaming abroad guide.

O2’s Features

O2 Priority

o2-priorityWith Priority, O2 customers get exclusive offers with high street brands, tickets to thousands of gigs & events across the UK and online entertainment discounts. To benefit from this service, you’ll need to download the free app from your app store. Priority is available on any compatible handset.

O2 Refresh

o2-refreshO2 offers flexibility to its customers and lets them change phones when they want. Basically, O2 Refresh splits a bill into two parts: a phone plan and an airtime plan. The phone plan is the cost of the phone you get from O2, and the airtime plan includes all your calls, texts and data allowances. When you feel like a phone upgrade is due, O2 will not lock you into a long term phone contract, but instead will let you pay off your phone plan. Your airtime plan will continue and you’ll be able to purchase a new device on a new contract.

<pDon’t forget though, you can only buy O2 Refresh directly from O2 and nowhere else.

O2 Bolt Ons

If you are running low on your data, minutes or texts, you can get a Bolt On from O2’s store to increase your allowance. Bolt Ons are simple add-ons offered by O2, starting from £3 a month. There are also other kinds of Bolt Ons, i.e. for calling abroad or for international roaming perks.

Unlimited Data Plans

O2 Disney +Unlimited Plans that O2 describes as “limitless data” start from £33/month for SIM-only customers. Unlimited data is also available on a range of Pay Monthly handsets through O2 Refresh.

The network only offers pay monthly unlimited data plans, and there are two different alternatives to choose from. The cheaper option is priced at £33/month and locks you in for 18 months. The second contract offer is for 12 months, priced at £35/month. Both deals include the ‘O2 Travel Inclusive Zone’ bolt on and 6 months Disney+.

A couple of points to note are that you are allowed to use a maximum of 650GB/month and O2 lets you tether to a maximum of 12 devices. If you want to check out what other networks are offering unlimited deals check out our detailed article.

Custom Plans

o2-custom-plansBuilding your own custom plan is a great feature. O2 puts the customer in control and lets them design a suitable plan for their needs. Customers get to choose how much they wish to pay upfront, how much data they want to have and they can spread the balance starting from as little as 3 months all the way up to 36 months. You’re even allowed to change your plan on a monthly basis depending on your needs. You can read our detailed guide on how to create an O2 custom SIM plan and learn all you need to know.

Data Rollover

o2-data-rolloverData rollover is available for O2’s PAYG users, which are also called Big Bundles and UK & International Bundles. Your unused data can roll over month to month without any base limit, as long as you renew your bundles. However, if you decide to change your bundle, your data rollover will reset. You also have to renew your bundle on the same day it expires or your unused data will expire.

Family Accounts

Family-plansWith O2’s family mobile plan you can get up to a 40% discount when you buy additional plans. For the discount to work, you’ll need to add a new eligible pay monthly tariff to your Family Plan. You can add up to 20 plans. If you bring in a family member to O2 via your referral link, both you and the family member can get a £25 Amazon voucher.

O2 Mobile Broadband

You can also invest in a mobile broadband deal and have solid internet access for all your devices wherever you go. You can read our detailed O2 Mobile Broadband Review to discover more about this service. 

Half Cooked’s Overall Breakdown

Half Cooked’s Overall Rating for O2: 4 out of 5 stars (4 / 5)

  • Network Coverage and Speeds – O2 has good 2G, 3G and 4G coverage, but the network’s data speeds are tracking behind its competitors. Their 5G is rather fast, but not the fastest.
  • Voice Call Quality – O2’s voice call quality is improving, however it’s still behind the likes of EE and Vodafone.
  • Tethering – O2 allows tethering, but limits customers in some ways.
  • Wi-Fi Calling & 4G Calling – Both voice call quality improving features are supported with specific plans
  • Wi-Fi Hotspots – O2 is one of the best when it comes to Wi-Fi hotspots. Wi-Fi Extra is a great perk for voice quality.
  • International Roaming – O2’s inclusive roaming options are great if you purchase a premium plan.
  • O2 Priority – The mobile network’s loyalty programme is one of the best, with a number of offers available daily.
  • O2 Refresh – When you buy a handset from O2, you can split your bill into two. One for your handset and one for your airtime.
  • O2 Bolts Ons – These are O2’s add-on options for when your price plans come short on your minutes, texts or data. You can also buy Bolt Ons for international calling and roaming abroad.
  • Unlimited Data Plans – O2’s unlimited data plans have a fair usage cap of 650GB. You can also tether to a maximum number of 12 devices.
  • Custom Plans – O2 allows you to build a custom plan when buying a handset from the O2 Store.
  • Data Rollover – This is only available on O2’s PAYG plans.
  • Family Plans – You can get up to 40% discount on O2’s family plans. Plus you’re allowed to have 20 contracts under one account.

o2 banner

Frequently Asked Questions

Does O2 support 5G?

Yes, O2 offers 5G coverage. At the time of writing O2’s 5G is live in 155 cities and towns.

Does O2 have Wi-Fi Calling?

Yes, O2 has Wi-Fi Calling. To benefit from this feature you have to be on a SIM Only contract and your device must be compatible.

Does O2 have 4G Calling?

Yes, O2 has 4G Calling. The network provides a VoLTE service, but you’ll have to be on a SIM Only plan and your handset must support this feature.

Is O2 Priority free?

Yes, O2 Priority is a free loyalty programme exclusively for O2 customers. However, while you’re on the app you’ll be using data.

Why can’t I access O2 Priority?

If you recently joined the O2 Network, it might be that Priority’s database hasn’t caught up yet, so your number might not be recognised. If it doesn’t work in a couple of days contact O2’s customer support.

How long does it take for a number to transfer on O2?

It shouldn’t take any longer than 24 hours. Usually you’ll be able to make phone calls with a couple hours, however texting might take longer. If you still can’t use your new SIM after 24 hours please contact O2’s customer support.

How long does it take for Amazon referral vouchers to arrive on O2?

The Amazon voucher reward will be sent to both parties within 3 months from your referred friend's connection.

How fast is O2’s 4G internet?

According to Open Signal’s April 2020 reports O2’s average 4G download speed is around 16.6Mbps and average upload speed is measured at 5.8Mbps.

Can I keep my number when switching to O2?

Yes, you can. It’s quite easy to keep your number. All you need is a unique PAC (Porting Authorisation Code) code, which you can get from your old network. You’ll deliver this code to O2 and they will do the rest.

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