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Compare UK SIM Only Deals
Analyze standard contracts, mid-contract price rises, and data rollover rules across O2, Sky Mobile, and Three. We provide objective data to help you select your next mobile plan.
Flagship SIM Only Plans
Compare the core monthly allowances, contract terms, and roaming policies for each primary network. Select a provider to check their current coverage map and complete your order.
O2 Custom Plan
Sky Roll Plan
Three Unlimited
30GB
High-speed data
25GB
With data rollover
Unlimited
5G data allowance
Includes EU roaming up to 25GB and custom contract lengths from 12 to 24 months. Subject to annual mid-contract price rises.
Unused data rolls forward for up to three years. Runs on the O2 network with no inclusive EU roaming.
Uncapped 5G speeds with unlimited UK tethering. Daily EU roaming fees apply. Best suited for high-density urban coverage.
What to Compare
Beyond the monthly cost, UK networks differ significantly in contract flexibility and secondary benefits. Assess these three core pillars before committing to a long-term contract.
Data Rollover
EU Roaming
Contract Terms
Sky Mobile allows you to save unused data for up to three years, whereas O2 and Three require you to use it or lose it monthly.
O2 retains inclusive EU roaming up to 25GB on standard plans. Three and Sky Mobile charge daily flat fees for European usage.
Three offers flexible rolling 1-month options alongside cheaper 24-month commitments. O2 offers split contracts to separate device and airtime costs.
SIM Only Guidance
Clear answers regarding UK mobile network switching, contract structures, and how our independent comparison platform works.
How do affiliate links work?
Keep your current number?
We display standard network pricing. If you click our links and complete a purchase, we receive a small commission from the provider. This process is entirely free for you.
Yes. Text 'PAC' to 65075 to receive your switching code. Give this code to your new network to transfer your mobile number within one working day.
What are mid-contract rises?
Which network is best?
Many UK networks increase monthly prices each April by the rate of inflation plus an extra 3.9%. We highlight these terms in our provider reviews.
Coverage depends heavily on your specific location. Three leads in urban 5G rollout, while O2 provides broader rural coverage. Always check official coverage maps.