What is O2?
O2, or as it’s officially known, Telefonica UK Limited, is the country’s second-largest telecommunications provider, with about 23.2 million subscribers at the end of 2024. At its founding way back in 1984 as Cellnet, the company was one of only two mobile networks in the UK, alongside Vodafone, and now has grown to become one of the most trusted and stable providers, known for its wide-ranging coverage and the abundant perks that often come with its service. The company says its network covers 99% of UK residents, and though some rural users report less-than-stellar access, it’s important to note that other mobile providers pay to use O2’s sprawling infrastructure. And while O2 is not considered the absolute fastest in the country, its customer service is solid, it has tariffs that cater to absolutely every kind of user, and its plans have tremendous flexibility depending on what you want.
O2 Prepaid plans
That flexibility includes the choice to select between prepaid or postpaid phone plans. The company’s postpaid plans are of the more traditional type, where you pay for service on a monthly basis and are locked into a contract, whether that’s a lengthy 12- or 24-month contract or a 30-day SIM-only contract. These monthly plans are usually best for heavy phone users, or those that can’t be fussed to keep their data balance up-to-date and prefer to just set it and forget it—though that may come with higher costs overall. O2’s prepaid plans allow you to pay as you go. Usually, for prepaid you purchase a bundle of talk, text, and data, and then use it until it runs out (or is about to run out), at which point you purchase a package to “top up” your balance and continue your usage. The advantages of these prepaid plans is that you only use what you pay for, with nothing extra, and your costs are often lower. Occasionally, some networks will put you in lower priority for network access, which can result in slightly slower speeds, but for the average user it’s not noticeable. Prepaid plans are ideal for most normal users, and are especially perfect for short-term residents, travellers, or those that value flexibility over everything else and are always hunting for the best deal. The key to getting the most out of a prepaid plan, however, is to always keep your balance topped up. This way, you avoid any unexpected lapses in service and get all the benefits of the O2 network with none of the downsides that come with sticky contracts. Luckily, mobiletopup.co.uk makes it incredibly easy to purchase top-up vouchers to keep your balance ready to use at any time. With just a few clicks, you can get a top-up card of anywhere from £10 to £50 delivered to your inbox within seconds with nearly any payment method you choose, backed by excellent security and supported by our top-notch customer service. Later, we’ll provide you with a step-by-step guide to using mobiletopup.co.uk to top up your O2 balance. But first, we’ll take a look at a few of the plans O2 has on offer to help you figure out what’s best for you.A wide range of plans, built for every kind of customer
All O2’s main plans include unlimited talk and text, and a SIM card if you need one. The best way to get access to O2’s network on a prepaid plan is probably through its “Big Bundles:”- 8GB for £10
- 25GB for £15
- 40GB for £20
- 125GB for £30
- 10GB for £10/month
- 30GB for £15/month
- 50GB for £20/month
- 150GB for £30/month
- 40GB for £10.99 monthly, increasing to £21.99 after six months
- 40GB for £15.24 monthly, with free roaming, increasing to £30.49 after six months
- Unlimited data, £16.00 monthly, increasing to £32.00 after six months
- Unlimited data, with roaming included for most destinations at £16.99 monthly, increasing to £33.99 after six months
- Unlimited data, with roaming included for nearly every destination at £21.24 monthly, increasing to £42.49 after six months
How to top up your O2 balance using mobiletopup.co.uk
First, you need to purchase your top-up voucher from mobiletopup.co.uk.- Go to https://www.mobiletopup.co.uk/o2
- Select your desired top-up amount.
- Enter the email address where the code will be delivered (must be valid).
- Choose your payment method from Mastercard, Visa, PayPal, Google Pay, American Express, Maestro, China UnionPay, or Discover.
- Click “secure payment” to complete the transaction. The code will arrive in the inbox of the email address you provided within seconds.
- Dial 4444 from your O2 mobile phone, or 0345 606 2277 from a landline.
- Follow the instructions to enter your voucher code when prompted.
O2 is great. Mobiletopup.co.uk makes it even better.
O2 offers one of the most flexible and reliable mobile experiences in the UK. With competitive data bundles, excellent coverage, and the added perk of data rollover, it’s easy to tailor your plan to your needs—especially if you’re keeping an eye on cost per GB. And with services like mobiletopup.co.uk, staying topped up and connected is fast, easy, and secure. Head to mobiletopup.co.uk and easily top up your O2 balance today!Frequently Asked Questions
How does O2 work?
O2 is a mobile telecommunications provider used by millions across the UK. To purchase a plan, you can do it online or in a local shop.
Is O2 reliable?
O2 is considered one of the most reliable and stable networks in the UK.
How do I activate an O2 card?
Follow the steps above to redeem an O2 prepaid voucher.
How do I top up O2 from another phone?
To top up from another phone, simply purchase a voucher at mobiletopup.co.uk, then dial 0345 606 2277 and follow the instructions.
How do I check my O2 balance?
You can check the current balance of your O2 credit by pressing *#10# and then hitting the call button.
Can I use my O2 top-up abroad?
Yep! To top up abroad, just follow the steps above. They’ll work anywhere in the world.
How do I top up O2 while travelling?
The same way you do otherwise! Just follow the steps above—they work anywhere.
Does O2 work in other countries?
Yes, O2 plans can include roaming, or you can pay an extra charge to access O2 service in other countries. Read this for more info.
How much does it cost to use O2 abroad?
It depends on which plan you’re using. Check roaming plans for more info.
Can I buy an O2 top-up for another country?
If you use your O2 phone abroad and pay for (or pay for a plan which includes) roaming, you can access O2 service. Here’s how.
What is the minimum amount to top up O2?
If using mobiletopup.co.uk, the minimum amount to top up is £10.
Can I transfer O2 credit to another number?
No, you cannot transfer O2 credit to another number.
Can I top up O2 for someone else?
Yes! The easiest way is to purchase a voucher from mobiletopup.co.uk and send it to them, but you can also using this method.
How to refund an O2 top-up?
There’s no guaranteed way to get a top up refunded, but try these methods.
How do I contact O2 customer service for top-up issues?
To reach O2 customer service for a prepaid plan, dial 4445 on your O2 mobile or 0344 8090222 from a landline.
Can I top up O2 with PayPal?
Yes, you can top up O2 with PayPal! Just follow the steps above.
Can I buy O2 top-up with a debit card or a credit card?
Yes, with both! Follow the steps above
Instant code delivery by email
Safe & secure payment
Certified reseller
O2
Direct delivery