O2 SIM only deals are a strong option if you’re looking for reliable coverage alongside a range of perks and flexible plans. As one of the UK’s four main networks, O2 offers widespread coverage and access to 4G and 5G where available. O2 stands out for its added benefits, including its Priority rewards scheme and inclusive roaming on selected plans, making it a good choice if you want more than just the basics.
Compare O2 SIM only deals
O2 offers a wide range of SIM only plans with different data allowances, all including unlimited UK calls and texts.
You can choose between 30-day, 12-month and 24-month plans, depending on how much flexibility you want. Prices vary depending on data allowance and contract length, with longer plans often offering better value.
Our best O2 SIMs this week
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O2 sim only
5G- 10GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Free roaming up to 25GB
- £7.00 per month
12 month contract From O2 -
O2 sim only
5G- 40GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Free roaming up to 25GB
- £8.00 per month
12 month contract From O2 -
O2 sim only
5G- 40GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Free roaming up to 25GB
- £8.00 per month
12 month contract From O2
Why choose an O2 SIM?
- Excellent coverage: O2’s network covers around 99% of the UK population for 4G
- Flexible plans: You'll have a choice of 30-day, 12-month and 24-month contracts
- Strong coverage performance: OpenSignal’s January 2026 UK Mobile Network Experience report found O2 won the overall Coverage Experience award, scoring 9.0 out of 10
- 5G included: Available at no extra cost on compatible devices and in supported areas. OpenSignal reported that O2 users detected a 5G signal 57.0% of the time, second behind EE’s 77.4%
- O2 Priority: Access to exclusive rewards, offers and presale tickets
- Volt benefits: Customers with Virgin Media broadband and an eligible O2 Pay Monthly plan can get Volt benefits, including double mobile data on eligible O2 plans and broadband speed boosts of up to 1Gbps.
- Roaming: EU roaming included on many plans, subject to a fair usage limit (typically up to 25GB), while some plans offer inclusive roaming in 75 destinations worldwide, including the EU, USA, Australia and Mexico
- Extras: Its plans includes perks like a three- or six-month free subscription to one of Disney +. Amazon Prime, Amazon Music, Audible, McAfee and more,
Read our full O2 review for more info.
O2’s best unlimited data SIMs
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O2 sim only
5G- Unlimited 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- 3 months Free Amazon Prime
- £23.00 per month
24 month contract From O2 -
O2 sim only
5G- Unlimited 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- 3 months Free Amazon Prime
- £23.00 per month
24 month contract From O2 -
O2 sim only
5G- Unlimited 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- 3 months Free Amazon Prime
- £23.00 per month
24 month contract From O2
O2 offers unlimited data plans across 30-day, 12-month and 24-month contracts, making them suitable for heavy users who stream, browse or use their phone as a hotspot.
These plans include unlimited UK calls and texts, along with 5G access where available. As with all networks, usage is subject to fair use policies.
O2’s best rolling contract SIMs
-
O2 sim only
5G- 10GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- £10.00 per month
1 month contract From O2 -
O2 sim only
5G- 150GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- £30.00 per month
1 month contract From O2 -
O2 sim only
5G- Unlimited 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- 3 months Free Amazon Prime
- £38.00 per month
1 month contract From O2
O2 offers 30-day rolling SIM only plans, giving you the flexibility to change or cancel your plan each month.
These plans include unlimited UK calls and texts and a range of data allowances. However, some perks, such as inclusive EU roaming, may not be available on all 30-day plans, so it’s worth checking the details.
O2’s best 12-month SIM deals
-
O2 sim only
5G- 10GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Free roaming up to 25GB
- £7.00 per month
12 month contract From O2 -
O2 sim only
5G- 50GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Free roaming up to 25GB
- £9.00 per month
12 month contract From O2 -
O2 sim only
5G- 100GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Free roaming up to 25GB
- £12.00 per month
12 month contract From O2
O2’s 12-month SIM only plans offer a balance between flexibility and value.
They typically include unlimited UK calls and texts, a choice of data allowances, and access to features like O2 Priority and inclusive EU roaming (subject to fair usage limits).
O2’s cheapest SIM only deals
O2’s cheapest SIM only deals are aimed at light users who mainly need calls, texts and a small amount of data.
While O2 isn’t always the lowest-cost provider, entry-level plans are competitively priced and include access to O2’s network and core features.
-
O2 sim only
5G- 10GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Free roaming up to 25GB
- £7.00 per month
12 month contract From O2 -
O2 sim only
5G- 10GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Free roaming up to 25GB
- £7.00 per month
12 month contract From O2 -
O2 sim only
5G- 10GB of 5G data
- Unlimited minutes
- Unlimited texts
- download speed limit
- Free roaming up to 25GB
- £7.00 per month
12 month contract From O2
What to look for in an O2 SIM only contract
When comparing O2 SIM only deals, you should keep an eye out for each plan's data allowance, contract length and monthly cost. The right deal depends on whether you mainly browse and message or regularly stream, hotspot and download large files.
Check whether the plan includes the extras you actually want, as O2 plans can come with perks such as Priority access, O2 Extras, EU roaming and, for eligible Virgin Media broadband customers, Volt benefits. These can add value, but only if you will use them regularly.
EU roaming is included in tariffs, subject to a roaming limit, while its plus plan includes selected 75 destinations worldwide, including the EU as well as Australia, the USA and Mexico. If you travel regularly, compare the roaming zones, data limits and fair use terms before choosing a plan.
Coverage should also be checked at postcode level. O2 performs strongly in OpenSignal’s Coverage Experience data, but real-world signal can still vary depending on location, terrain, building type, congestion and device. Ofcom’s mobile coverage checker is useful for comparing predicted signal by provider before you buy.
Is O2 a good network?
O2 is a good network if you prioritise coverage, perks and roaming over the very fastest speeds. OpenSignal’s January 2026 UK report found that O2 won the overall Coverage Experience award, scoring 9.0 out of 10, which put it ahead of EE, Vodafone and Three for that measure.
O2 also has a strong selection of benefits. SIM only customers can access O2 Priority, while selected plans include Extras or wider roaming options. Customers who also have eligible Virgin Media broadband may be able to use Volt benefits, including double mobile data on eligible O2 plans and broadband speed boosts of up to 1Gbps.
The main trade-off is speed - OpenSignal’s January 2026 report put O2 fourth for overall Download Speed Experience at 32.8Mbps, behind EE, Three and Vodafone. That should still be enough for everyday browsing, maps, messaging, music and standard video streaming, but O2 may not be the strongest choice if your priority is the fastest possible mobile data.
It's also worth noting that O2 does not have a fantastic reputation among its customers. It's rated a Bad 1.2 stars on Trustpilot from over 20,000 reviews, while Ofcom research shows that O2's mobile platform is the most complained about of all the providers it assessed.
How does Vodafone compare to others?
Network | Price | Speed | Coverage | Best for |
|---|---|---|---|---|
O2 | ££ | Medium | Excellent | Coverage and perks |
££ | Fast | Strong | Balanced performance and add-ons | |
£££ | Fastest | Excellent | Premium performance | |
£ | Fast | Good | 5G speed and value | |
£ | Fast | Strong | Streaming perks |
Data sourced from Opensignal Mobile Network Experience Report January 2026.
Can I use my O2 SIM abroad?
Yes, O2 allows you to use your allowance in its Europe Zone on many plans, subject to a fair usage limit (typically up to 25GB). Roaming beyond Europe may require a daily charge or add-on, depending on your plan.
Can I get 5G enabled O2 SIMs?
Yes, all O2 SIMs are 5G-ready. You’ll need a compatible device and to be in an area with 5G coverage to access it.
Can I keep my mobile number if I switch to an O2 SIM-only deal?
Yes, you can keep your number by requesting a PAC (port authorisation code) from your current provider and giving it to O2.
Do I need an unlocked phone to use an O2 SIM?
Yes, your phone needs to be unlocked to use an O2 SIM. Most phones sold in recent years are already unlocked.
Are O2 SIM-only deals cheaper than contract?
SIM-only deals are often cheaper overall because you’re not paying for a handset. However, phone contracts can spread the cost of a device over time, which may suit some budgets.
Is O2 a good choice for rural areas?
O2 can be a good choice for rural areas, especially if coverage is your main priority. OpenSignal ranked O2 first for overall Coverage Experience in January 2026, with a score of 9.0 out of 10. Rural signal can still vary by postcode, terrain and indoor location, so check O2 coverage at your address before choosing a plan.
Is O2 a good network for gaming and streaming?
O2 should be suitable for streaming and casual gaming where coverage is strong. However, OpenSignal’s January 2026 report put O2 behind EE, Three and Vodafone for overall download speed, with O2 at 32.8Mbps. For competitive gaming, heavy hotspot use or regular high-resolution streaming, compare O2’s local performance against the other major networks before choosing a plan.
