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O2 SIM-only review

O2 has a range of SIM-only deals on 12-month or 30-day rolling contracts, all of which are ideal if you’re happy with your current mobile phone. O2 has good coverage throughout the UK and all SIMs come with access to its public wi-fi network and Priority deals.

Compared to the range of budget mobile offers on the market, O2’s SIM-only deals aren’t the cheapest, especially if you want a lot of data. Read on to find out if O2 is right for you.

Cable.co.uk overall rating

O2 has a good variety of SIM-only contracts, all of which include unlimited texts. They come on either 12-month or 30-day rolling contracts and offer some great extras, like access to public wi-fi and O2 Priority rewards. Just bear in mind that if you want a lot of data, you might pay more than you would with a budget provider.

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Coverage & data speed



According to the most recent Ofcom report, O2’s 3G signal covers 98% of UK premises. This is not as extensive as either EE and Three, which both cover 98%, but higher than Vodafone, which only covers 96%. As O2’s faster 4G network is still rolling out, its 4G coverage is lower. Currently, it covers 97% of UK premises, coming in behind EE, which has 99% coverage.

When it comes to speed, O2’s 3G downloads average out at 5Mbps according to Ofcom. This is still fast enough to let you check social media, browse the internet and send emails without much waiting around. O2’s 4G speed is better, running at 18Mbps. This will let you download and stream videos on your mobile quite comfortably without much buffering.

3G coverage
4G coverage
Average 3G speed*
Average 4G speed*
Call allowance
250 minutes – unlimited
Text allowance
Data allowance
250MB – 16GB
Minimum contract
30 days
*According to Ofcom
Prices from
3G coverage 98%
4G coverage 97%
Average 3G speed* 5Mbps
Average 4G speed* 18Mbps
Call allowance 250 minutes – unlimited
Text allowance Unlimited
Data allowance 250MB – 16GB
Minimum contract 30 days
Prices from £10 per month
*According to Ofcom

Scroll horizontally for more information.

Data usage



O2 offers SIM cards with usage limits of up to 16GB, but it does not offer a plan with unlimited data. O2 sells additional ‘Bolt Ons’, which you can buy to increase your monthly allowance. If you reach your maximum data allowance O2, will either throttle or stop your connection, but it will warn you when you’re nearing your limit.

O2 allows tethering on all its plans. Tethering is the ability to use your mobile as a wireless router, allowing other devices to use your internet connection. If you’re interested in mobile broadband, O2 has a range of personal hotspot devices. O2 also has a network of public wi-fi hotspots in thousands of locations nationwide, so you can connect to the internet without eating through your data.

Calls & texts



All of O2’s SIMs come with unlimited texts, while the minutes allowance ranges from 250 to unlimited. These inclusive minutes can be used to call any standard landline or mobile number, regardless of network. This excludes calls to special numbers like 0800 numbers and non-geographic numbers.

Once you’ve used your call allowance, you’ll be charged 40p per minute for every call you make. You can get additional minutes with a More Minutes Bolt On, which gives you an additional 50 minutes for just £1.

Extra features



O2 really comes into its own with its perks. There are a number of apps which are free to download for all O2 customers, and these can add value to your package. The O2 wi-fi app is the highlight here. This gives you access to O2’s public wi-fi network, so you can connect to the internet at thousands of locations throughout the UK, giving you a faster internet speed and saving your data allowance.

Customers also receive access to O2 Priority, which gives advance access to concert tickets, as well as special offers from high street stores and competitions. One of the benefits of going with O2 is that it has a high street presence, so any technical help and advice on choosing your next phone can be done face-to-face from any in-store O2 Gurus.

Value for money



As a premium mobile phone operator, O2's tariffs sit fairly high on the market, especially when compared to virtual mobile operators like giffgaff or Virgin Mobile. Value is added to your SIM through the perks and extras that come with it, but if you’re just looking for something simple, you might want to look elsewhere.

O2’s SIMs come on either 12-month or 30-day contracts. The extra flexibility of the 30-day contracts makes those SIMs a little more expensive. If you’re looking for a large amount of data, O2 might not be the best option. Its most expensive SIM is £28 per month and gives you 16GB of data on a 12-month contract.

Overall Rating


O2 is a premium brand with good coverage and a solid service. It has a wide variety of SIMs on 12-month and 30-day rolling contracts, all of which come with unlimited texts. The SIMs are comparable in price to most other mobile phone deals, and range from 250MB to 16GB.

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