The great thing about Telefonica-owned O2 is that it has tons and tons of mobile plans, enough to suit anyone. And that includes a good deck of SIM-only deals that you can use in any unlocked phone.
You get reasonably-priced tariffs, a wide choice of monthly allowances, and some pretty good benefits too - like O2 Priority. In this guide, we'll take you through what you get from O2, and how to choose a SIM deal.
What SIM-only deals can I get from O2?
O2 has a huge range of SIM deals. There's something for everyone, regardless of how much you use your phone.
Monthly allowances range from 200MB data with 150 calling minutes and texts, up to 30GB with unlimited minutes and texts. Most O2 SIM plans come with unlimited texts, in fact, and quite a lot have unlimited calls too - so it's easy to find a plan if you're a chatterbox.
SIMs are available on either 12-month or one-month contracts, each of which come with their own advantages. Longer term 12-month plans cost less per month, and higher allowances are available; while one-month deals give you more flexibility.
Perks and benefits
All pay-monthly SIMs from O2 get you these benefits:
- O2 Priority, which gives you exclusive offers and vouchers for high street stores, restaurants, events, and more
- Priority Tickets - buy tickets for big events like gigs before they go on general sale
- VIP treatment at O2 venues
- Free access to O2 public Wi-Fi hotspots
- Free help and advice with your phone from the O2 Gurus
How to compare O2 SIM-only deals
Comparing O2 SIM deals is easy - just use the table at the top of this page. You can see all the deals together, compare what you can get, and filter them down so you only see the ones that suit what you need.
Think about things like:
- Allowance - how much data and how many minutes and texts do you need per month?
- Contract length - choose between a 12-month or a 30-day plan
- Price - if you have a budget, choose the maximum you want to pay each month in the cost filter
Click on the deal you like best, and we'll take you to O2's website so you can sign up and get started.
If you're not convinced O2 is the network you want, that's no problem - you can compare its deals right next to those from other providers too. Just select the networks whose SIMs you'd like to see and we'll show you the lot. Or, compare all SIM deals here.
Can I get an unlimited data O2 SIM?
No, we're afraid unlimited data isn't available with O2. The maximum monthly data allowance you can get is 30GB, on a 12-month contract. That's still quite a lot of data - it's enough to stream about 30 hours of HD video, or send several million WhatsApp messages.
If you don't think 30GB is enough for you, however, you may need to take a look at unlimited and big data options from other networks instead.
What's the cheapest O2 SIM-only deal?
The cheapest mobile SIM deal you can get from O2 is a 30-day plan that comes with 200MB data, 150 minutes, and 150 texts per month.
O2's cheapest SIMs have very low allowances - we're talking less than 1GB of data, and only a few hundred minutes. They're great if you don't use your phone much and just want a bit of service (and O2 Priority, of course) but not so much if you're a heavy user.
To find the cheapest deal that fits your use, use our comparison table. Adjust the filters to make sure you only see SIMs that have enough monthly allowance for you, and then sort the whole table by monthly cost. You'll see the lowest-priced deals right at the top.
You'll generally find that 12-month plans work out cheaper per month than 30-day ones, so it's worth the commitment if you really want to save money. And sometimes there are limited time deals that are worth pouncing on - keep a beady eye out for those.
Is an O2 SIM deal cheaper than a phone contract?
Yes - it's almost always cheaper in the long run to buy a phone outright and take out a SIM-only deal.
However, because of the way O2's 'Refresh' contracts work, they're actually not that much more expensive than going SIM-only. They split your bill up to show you how much you're paying for your device and how much you're paying for your SIM - you can see that the only extra cost you pay on the handset is interest.
So, yes, going SIM-only costs you less... But if you do want the benefits of a phone contract plan - like lower upfront costs, a nice new phone in your hand today, and free screen replacements courtesy of O2 - it's good to know you won't be ripped off.
Can I upgrade an O2 SIM-only deal?
O2 has a pretty good upgrades system going. It's super easy to switch to another tariff once your SIM contract runs out, and sometimes there are special existing customer deals available.
There are even better upgrades available if you go for a Refresh phone contract, including the ability to pay off your handset cost and get a new one whenever you like.
Of course, the easiest O2 deals to upgrade are its 30-day SIMs - which you can change every single month, if you want to.
Can I keep my number if I switch to an O2 SIM-only deal?
Yes - it's almost always possible to keep your current phone number when you switch to a new network.
1) Choose a new SIM-only plan - compare deals and sign up to one that you like the look of. Your SIM will be sent through the post to you. While you're waiting…
2) Contact your current provider and request your PAC (porting authorisation code) - you can request your code in a few ways - online, via text and even by post if you're really old-school. If you phone, they may try to talk you into sticking with them, but stick to your guns if this happens. They'll send you the PAC as a text message within two hours.
3) Give the PAC to your new network - when your new SIM arrives, it will have a new number. To change it to the old one, contact your network and give them the PAC code. They'll take care of porting the number over. It could be as fast as one working day before the old number's transferred, but be aware that on occasion it can take a little more time.
It may sound complicated, but it's very simple in practice. If you want a bit more detail, check out our full guide to keeping your phone number:
What size SIM card do I need?
There are three SIM card sizes you can get:
- Standard SIM card - 15mm x 25mm, commonly used in older feature phones
- Micro SIM card - 12mm x 15mm, used in some smartphones, primarily older models
- Nano SIM card - 8.8m x 12.3mm, used in most modern phones, including popular handsets like the iPhone 8 and Samsung Galaxy S8
Don't worry if you have no idea which size your phone takes. Most networks will send you a 3-in-1 SIM, designed to fit into any handset. It'll come encased in plastic, and you can pop it out into the size you want.
In other words, don't stress about SIM size when comparing deals. Whichever you choose, the SIM card will fit in your phone.
Does my phone have to be unlocked to use an O2 SIM?
Some phones are locked onto a particular network, and will need to be unlocked before you can use another company's SIM. Fortunately, this is really easy to do. To find out if your phone is locked, pop in a friend's SIM card - they'll need to be on another network obviously. If it works, then your phone is good to go - otherwise, you'll need to contact your current operator and ask them to unlock it.
Different networks have different rules on unlocking. Some examples are:
- Three - all handsets are unlocked out of the box.
- O2 - phones are locked, but O2 will unlock them for free when you're out of contract. Pay-as-you-go (PAYG) customers will have to pay though.
- Vodafone - phones are locked, but Vodafone will unlock for free.
- EE - phones are locked, but EE will unlock for free - so long as you're out of contract. PAYG customers must wait 12 months after purchasing to unlock.
- Those are just the major networks. To find out more about unlocking your mobile, check our full guide:
More SIM-only deals
Take a look at the SIM deals you can get from other providers too:
- Asda Mobile SIM-only deals
- EE SIM-only deals
- giffgaff SIM-only deals
- iD Mobile SIM-only deals
- Plusnet Mobile SIM-only deals
- Sky Mobile SIM-only deals
- Smarty SIM-only deals
- Tesco Mobile SIM-only deals
- Three SIM-only deals
- TPO Mobile SIM-only deals
- Virgin Mobile SIM-only deals
- Vodafone SIM-only deals
- VOXI SIM-only deals