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The Best O2 SIM Only Plans – June 2021

O2 offers a great range of high value SIM only plans for all types of mobile customers. Read on to find the right plan for you!


O2 is one of the four major mobile networks in the UK, and they offer great value SIM deal, coupled with market leading entertainment options.

The carrier’s SIM only deals are usually a little more expensive than most MVNOs and some of the MNOs, but you get 5G at no additional cost, access to O2 Priority, O2 Wi-Fi Extra, 4G Calling, Wi-Fi Calling and more. These features significantly increase the value of O2’s tariffs, and on top of that you can even customise your own plan and split your bill into two parts if you’re buying a handset directly from O2.

Latest Offer: 120GB for £20 w/ 6 months free Disney+

O2 is offering 120GB of data bundled with 6 months free Disney + and Apple Music for just £20/month! This is a 24-month contract, but offers great value and includes unlimited UK minutes & texts. If Disney+ isn’t for you, there are a number of other perks to choose from, click through to find out.

In this article, we will help you establish what type of mobile user you are and help direct you towards the best SIM only plans available on O2. We won’t talk about O2’s network coverage and data speeds, and solely focus on their SIM offers. However, we have an extensive O2 Review that covers everything you need to know about the network.

You can find all kinds of mobile deals on O2 from unlimited data plans to 30-day rolling SIM only contracts. They also offer a traditional pay as you go service as well as PAYG bundles that require no credit checks. Sadly, 5G coverage isn’t available to O2 PAYG customers yet. Keep reading to find out the most suitable O2 SIM only deal for you.

Plans and Pricing

O2 pretty much covers all contract terms, offering 30-day, 12-month and 18-month contracts, as well as a traditional pay as you go service and pay as you go bundles.

The carrier treats their pay monthly customers quite well, offering freebies and prize draws on O2 Priority. They also offer free access to O2 WiFi. All O2 SIM only plans have 5G inclusive, but you’ll need a 5G SIM and a 5G ready device in order to benefit from super-fast data speeds and connection.

The network’s PAYG service isn’t that great and you don’t get any fancy benefits unless you purchase a monthly bundle, but at least you still have that option.

Best O2 SIM Only Plan For Light Data Users

We believe the best O2 SIM only plan for light mobile users is the network’s 10GB for £8 a month deal. It’s a 12-month contract that includes 6 months of Disney+, unlimited UK minutes & texts, O2 Priority, O2 WiFi and more. You’ll have to undergo a credit check though, as this is a 12 month deal.

If you expect to rarely ever have to use your data or expect to be connected to Wi-Fi when you do, we also recommend O2’s £5 PAYG bundle. It gets you unlimited UK calls and texts, but you’re not given any data allowance. You can still use data, but it will come out of your credits and it may still prove costly, depending on how often you consume it.

Best O2 SIM Only Plan For Moderate Data Users

If you don’t mind being locked in for 18-months with your mobile network, O2 offers 30GB of data, priced at just £15/month. Just like any other O2 pay monthly plan, this offer comes with unlimited UK minutes & texts, 6 months of free Disney+, Wi-Fi Calling, 4G Calling, O2 Priority and O2 WiFi.

We know, 30GB of data per month sounds like a bit of an overkill for moderate data users, but this is really the sweet spot when it comes to O2’s offers. The next best offer is 10GB for £8 on a 12 month airtime plan, but if you’re regularly using your mobile data allowance, 10GB of data may not be enough for you, especially for streaming high quality videos and music everyday. Add tethering to the list and you’ll run out of data in no time.

This is a limited time offer and it ends on the 24th March so hurry!

Best O2 SIM Only Plan For Heavy Data Users

If you’re a user than burns through a tonne of data on a daily basis, O2 also has you covered. Whether you’re regularly streaming high quality videos on YouTube, Netflix, Amazon, Disney +, or tethering a number of devices, O2 has you covered with a 150GB data plan priced at £20/month.

This offer is a 12-month contract, and it includes all the basics such as unlimited minutes & texts, O2 Priority & O2 WiFi. Additionally, this plan also comes with the O2 Travel Inclusive Zone feature, which allows you to roam freely in 75 destinations across the world, including the USA. This offer ends on the 24th March.

Best O2 Unlimited Data Plan

Unlike Three or Vodafone, there’s not much variety on O2 when it comes to unlimited data plans. The network offers only two unlimited data plans which are essentially identical and the only difference between them is the length of contract and monthly price.

You can either sign up for an 18-month contract priced at £33 a month or a 12-month contract priced at £35 a month. O2’s unlimited data plans come with all the regular perks of their other plans as well as the ability to use your UK allowances in 75 destinations, USA included.

Keep in mind that O2 doesn’t actually offer truly unlimited data. The network says you’re allowed to use up to 650GB of data per month, and if you regularly pass this limit surcharges will apply. You are permitted to tether to other devices, but you’re limited to 12 devices at most. O2 also has the right to terminate your contract, if you ignore these restrictions or if they think you’re using your SIM for commercial purposes. If you are a commercial customer, you can check out O2’s business SIM deals and get cheaper prices.

If all you want is unlimited data and download speeds aren’t that important, you can always check out Three’s unlimited data plan with 5G, which is priced at £16 a month. It’s a 12-month contract, but it offers great value and it’s the cheapest unlimited data plan on the market. It’s significantly cheaper than O2’s unlimited data plans.

Cheapest O2 SIM Only Plan

If you’re looking for the absolute cheapest O2 30-day offer on the mobile market, the network offers a pay as you go bundle that requires no credit checks, priced at only £5 a month. However, this PAYG bundle doesn’t have any data allowance. You also have to top up at least £10 in order to purchase this bundle.

The second cheapest option is the network’s 10GB for £8 a month deal, but you’ll have to pass O2’s credit check and you’ll be locked in with the network for a whole year. Cancelling your mobile contract is never easy, so we’d recommend making sure you’ll be satisfied with O2’s coverage in your area before you make your final decision.

Alternatively, you can choose a SIM only deal from giffgaff, a mobile virtual network operator powered and owned by O2. These two networks offer identical network coverage and data speeds, however, giffgaff’s goodybags (their commitment-free SIM only plans) are priced a little cheaper and offer complete freedom. You can get 500MB of data and unlimited UK minutes & texts for £6 a month on giffgaff, no strings attached.

Best O2 SIM Only Plan For International Roaming

O2’s regular SIM only deals let you roam freely across Europe, in 48 destinations. However, if you sign up for a tariff that gets you 100GB of data or more, your roaming scheme is automatically updated to the O2 Travel Inclusive Zone, which lets you use your UK allowances in 75 destinations across the world.

If you’re going to travel outside Europe, and your destinations are included in this scheme, we recommend opting for O2’s 150GB for £20/month tariff. It’s a 12-month contract and it’s definitely the best option out there for O2 customers. The second best option is 100GB of data for £20/month, 18-month contract. This deal will lock you in with the network for 6 more months and you’ll get 50GB less data, yet you’ll be paying the same.

You might still want to check out Three’s Go Roam scheme, or Vodafone’s Unlimited Max plan, which includes the best free roaming scheme in the UK. Vodafone’s Global Roaming Plus allows you to roam freely in Turkey. This is the only scheme that offers free roaming in Turkey at the moment.

Best O2 SIM Only Plan For Tethering

First things first, we need to talk about how tethering works. Tethering refers to turning your handset into a mobile hotspot to share your mobile data with other compatible devices. These devices can be laptops, tablets, other smartphones and such. When you’re tethering to other devices, your data gets eaten at a much faster rate. Connected devices may be using data in the background without you noticing.

All O2 SIM plans allow tethering, but there’s a limit to how many devices you can tether to. O2 says you can only share your mobile data with 12 other devices, and past this point they’ll consider it as commercial use and punish you accordingly. This means surcharges may apply or O2 might downgrade your plan or even cancel your contract.

Since tethering is a data-heavy action, we recommend opting for at least an O2 tariff with 100GB of data, preferably more or even an unlimited data plan. Keep in mind that O2’s unlimited data plans aren’t truly unlimited and there’s a fair usage limit of 650GB per month.

Best O2 SIM Only Plan For Students

As a student, you are eligible for a 20% student discount on your O2 SIM plan, but only when you pick up a phone, tablet or mobile broadband device on O2 Refresh. You won’t be getting a discount on the device though, just on your airtime plan that covers your calls, texts and data. The network also offers a 20% discount on accessories.

Each student has different needs, so singling out an O2 SIM Only plan isn’t the best way to go. In any case, we believe O2’s 10GB for £8/month plan is a great choice. It comes with tons of perks and key features, it’s competitively priced and offers enough data for a regular mobile user.

For students on a tighter budget we strongly recommend checking out SMARTY’s SIM only plans. All SMARTY plans are commitment-free, meaning you don’t have to pass a credit check. Plus SMARTY SIM only plans offer great value for super-cheap prices. On top of that, you can create a family/group mobile plan with your fellow students and get a 10% discount on each additional deal. Alternatively, you can read our UK Student Mobile plans guide and see what other networks are offering discounts and special deals for students living in the UK.

Network Coverage & Data Speeds

It’s hard to measure how good a mobile network’s network coverage is, but thanks to independent testing bodies such as Open Signal and OOKLA, we can start to have an idea. In terms of coverage, we have two key factors to look at: A network’s population coverage and landmass coverage. O2 does well in the first area; the carrier’s population coverage is over 99%, but landmass coverage is more important. At the start of 2020, O2 was behind all its competitors, but the network improved in this area and now their 4G population coverage is above 90%, meaning they’re almost on par with EE and Vodafone, leaving Three behind.

However, the network’s 4G data speeds tell another story. When we examine the speed test results published by Open Signal in October 2020, we see O2 at the bottom of the list ranking last. O2 has the slowest average 4G download and upload speeds among the four major network operators. O2’s average 4G download speed is around 18Mbps and upload speed is around 6Mbps. These data speeds aren’t necessarily bad if you’re not going to share your mobile data with others. You can easily stream full HD content on YouTube, Netflix, Prime Video and so on, but there’s definitely a lot of room for improvement. Watching 4K videos on the other hand wouldn’t be as smooth. You’d have to wait for videos to buffer at times.

For comparison, EE are the fastest 4G network in the UK. Their average 4G download speeds are at 36.4Mbps, upload speeds are around 9 to 10Mbps. You can read our detailed EE Review to learn more about the network, or check out our O2 vs EE comparison and discover which network is more suitable for you.

5G Coverage

In the UK, O2 5G is available to all of their pay monthly customers, but sadly O2 PAYG customers can’t benefit from super-fast 5G download speeds.

At the moment, O2 5G is available in 193 cities and towns. The network has been rolling out its 5G network at a faster rate than its competitors. Not long ago they were behind Three, EE and Vodafone, but now O2 has the second most 5G Coverage in the UK.

O2 is also the second fastest 5G network in the country with average download speeds of 177Mbps, per OOKLA’s October 2020 test results. You’ll need a 5G ready phone and a 5G SIM from O2, and also be in an area with O2 5G, if you wish to benefit from super-fast download speeds.

As an alternative, we can suggest checking out Three’s SIM Only plans. The network offers 5G at no extra cost to all their customers, including PAYG users. On top of that, Three is the fastest 5G network in the UK at the moment. Check out our Three Review or read our O2 vs Three comparison to learn more!

How Much Mobile Data Do I Need?

Actually, we already covered this section extensively in the past. You can read our ‘How much mobile data do I need?’ guide for a more detailed approach. In this section, we’ll focus on O2’s SIM only offers.


O2’s SIM only deals are usually aimed at customers looking for extra benefits over cheap prices. In today’s world, 500MB of data isn’t enough for much and we can pretty much guarantee at one time or another you’ll spend more than this without noticing and end up with a bill shock. If you mainly use your Wi-Fi, 1GB to 5GB data can be enough, but you’ll always be at risk of spending more than your allowance.

Remember that even the lightest data activities such as going through your emails and checking only a few web pages a day can burn through 50 to 100MB a day.


For a moderate mobile data user 8 to 10GB should be more than enough. Having said that, O2 doesn’t offer much of a variety for moderate users. Your two options are picking a 10GB plan or a 30GB plan. The 30GB plan is an 18-month contract. We think 18 months is a long time to tie yourself into a contract, and given how cancelling a mobile contract can be a major pain, we recommend you think twice before committing.


These plans are large and should cover most day to day internet activities and even allow you to stream high quality videos and music on a regular basis. Getting a 100GB or above data plan from O2 also gets you free access to the network’s premium roaming scheme, which lets you use your UK allowances in 75 destinations, including the USA.

If you’re going to be streaming content on Prime, Disney +, Netflix, YouTube etc. on a daily basis, for a few hours every day, 50GB will not be enough. We’d recommend going for 100GB or 150GB in this case. You’ll end up spending £2 more per month, but it’s worth it.

Unlimited Data

O2’s unlimited data plans are not truly unlimited. There’s a fair usage limit of 650GB per month. While this is still a lot of data and most you can get from O2, it’s still limited. On top of that, if you’re regularly sharing your mobile data with other devices for heavy activities such as streaming 4K videos etc. your data will get eaten up at a much faster rate.

Just keep in mind that you’re not getting unlimited data, but 650GB if you choose one of O2’s unlimited data plans.

Can I Keep My Phone Number?

Yes, you can keep your phone number when switching to a new mobile network. It doesn’t matter which network you’re joining or leaving. Just get in contact with your current network and ask for your PAC code. A PAC code will be given to you immediately over the phone or in about 2 hours by text. Give this code to O2 and they’ll do the rest. It shouldn’t take more than a day to completely move your number to O2, but in some cases it can take up to 2 days.


Does O2 have 5G?

Yes, O2 has a 5G service and it’s fast! However, at the moment 5G is only available to O2 pay monthly customers.

How fast is O2 5G?

Per OOKLA (speedtest.net) O2’s average 5G download speeds are around 170Mbps. This is really fast. In fact, about 10 times faster than O2 4G.

Does O2 Pay As You Go have 5G?

No, unfortunately O2 5G is only available to the network’s pay monthly customers at the moment. We expect this to change soon though.

Does O2 have 4G Calling and Wi-Fi Calling?

Yes, O2 offers both these features to their pay monthly customers. Plus the network provides a service called O2 WiFi Extra; if your device supports WiFi Calling, you’ll automatically and seamlessly connect to O2’s free WiFi service reserved for O2 customers. Your voice call quality will drastically improve if you’re around an O2 WiFi hotspot.

Do I have to pass a credit check to join O2?

Yes, but only if you want to sign up for a mobile phone contract or SIM only pay monthly contract. O2’s pay as you go service is completely commitment-free.