By DealPriceCheck · Published and checked 6 September 2026
You don’t have to buy a SIM from O2 to use O2’s mobile network. Tesco Mobile, giffgaff and Sky Mobile use O2 infrastructure while selling their own plans and setting their own terms.
Ofcom lists all three as using the O2 network, and O2 itself names giffgaff, Tesco Mobile and Sky Mobile as providers running on its infrastructure. They all share O2 underneath, but the plans are not interchangeable.
Tesco Mobile leans heavily on Clubcard pricing and free EU roaming. giffgaff focuses on flexible plans, online account management and a community model. Sky Mobile stands out for data rollover through Sky Piggybank and support for O2’s newer 5G+ technology on selected devices.
There is also one old name that still causes confusion: Virgin Mobile. The brand stopped trading for new mobile plans in August 2023 and customers were moved onto O2 plans. It is not a current standalone O2 MVNO in a 2026 comparison.
O2-based mobile networks at a glance
Provider
O2-based?
5G
eSIM
Typical plan style
Main reason to compare
Tesco Mobile
Yes
Yes
Yes
SIM-only, PAYG and handset contracts
Clubcard pricing, no EU roaming fees and retail-store presence
giffgaff
Yes
Yes
Yes
Flexible rolling, PAYG and longer plans
Flexible plans, community model and up to 5GB EU roaming
Sky Mobile
Yes
Yes / 5G+ on selected devices
Yes
Monthly plans
Sky Piggybank rollover and selected 5G+ support
Virgin Mobile
Closed
Migrated to O2
Legacy only
No longer sold
Former brand; customers moved to O2
DealPriceCheck note: Provider features and roaming rules can change. Always check the exact plan and local coverage before switching.
Selected providers — not whole of market. Prices and availability can change; check the provider’s website before purchase.
Tesco Mobile
Tesco Mobile is one of the clearest alternatives to buying directly from O2. Its own site says it is powered by O2’s network, with 99% UK 4G population coverage and 5G available across many towns and cities.
Tesco Mobile is especially relevant if you already use Tesco Clubcard. Clubcard Price deals can freeze the basic monthly usage price for the length of the contract, making the core monthly cost easier to predict than plans that can rise mid-contract. It also offers Home From Home roaming across 48 destinations in the EU and beyond with no extra roaming fee, subject to fair use. Tesco Mobile now supports eSIM too.
Tesco Mobile may suit you if:
O2 coverage works well where you live;
you already use Clubcard;
predictable contract pricing and included European roaming matter;
you want eSIM or access to physical retail stores.
The main thing not to assume is that “powered by O2” means you are buying an O2 plan. Tesco Mobile controls its own pricing, support, contract terms and perks.
giffgaff
giffgaff also runs on O2 and says so directly on its own site. It is one of the better-known O2 piggyback networks because the proposition feels quite different from O2 itself.
giffgaff sells flexible rolling plans, pay-as-you-go options and longer contracts. 4G and 5G are included on current plans, and the provider supports eSIM. Eligible plans include up to 5GB of EU roaming data in the EU and selected destinations, assuming the plan contains at least 5GB of UK data. If the UK allowance is smaller, the roaming allowance is capped at that lower amount.
giffgaff may suit you if:
you want O2-based coverage and flexible plan options;
you want 5G and eSIM;
up to 5GB of included EU roaming is enough;
you are comfortable managing most things online.
The network may be O2, but the plan structure, support experience and extras are giffgaff’s own.
Sky Mobile
Sky Mobile is particularly interesting in 2026 because it is not limited to standard O2 4G and 5G. Ofcom lists Sky Mobile as using O2, and O2’s own guidance names Sky Mobile as one of the providers on its network.
Sky’s best-known differentiator is Sky Piggybank. Unused data from eligible plans rolls into Piggybank, where it can be used later, shared across SIMs on the account or exchanged for rewards. Sky’s current terms say unused Piggybank data lasts 12 months before expiring.
Sky Mobile also supports 5G, eSIM, Wi-Fi Calling, 4G Calling, Sky Piggybank and sharing rolled data between eligible SIMs. Its newer 5G+ service uses standalone 5G. To use it, customers need an eligible handset, an eSIM, current software and the free 5G Network add-on.
Roaming is less generous than Tesco Mobile’s simple Home From Home proposition. Sky uses Roaming Passport Plus and paid roaming terms in many popular destinations.
Sky Mobile may suit you if:
you already use Sky services;
data rollover or sharing saved data is valuable;
you want eSIM and Wi-Fi Calling;
you are interested in 5G+ on a compatible device;
roaming is not the main reason you are choosing a provider.
What happened to Virgin Mobile?
Virgin Mobile is still mentioned on older O2-network lists, but it should not appear as an active standalone choice in 2026. Virgin Media says it stopped trading as Virgin Mobile at the end of August 2023. Customers were moved onto equivalent O2 plans and new Virgin Mobile plans are no longer sold.
Is an O2 MVNO the same as O2?
No. Using O2 infrastructure only tells you which physical network carries the service. Price, contract terms, support, roaming and extras can still differ.
5G, 5G+ and eSIM
The three main O2-based alternatives all offer 5G and eSIM. Newer standalone 5G features can still differ: O2 calls its standalone service 5G+, and Sky Mobile supports it on selected compatible devices. Do not assume every O2-based provider receives identical standalone 5G access.
Roaming and data rollover
Tesco Mobile includes Home From Home in 48 destinations, while giffgaff includes up to 5GB of EU roaming data on eligible plans. Sky Mobile uses a paid roaming model in many destinations. Sky also stands apart through Piggybank: unused data from eligible plans can remain available for up to 12 months.
Customer support
Tesco Mobile, giffgaff and Sky each manage their own customers. Running over O2 infrastructure does not turn the customer into an O2 retail customer.
Do O2-based providers get the same coverage as O2?
The underlying O2 radio network is the starting point. Tesco Mobile says it is powered by O2, giffgaff says it is powered by O2, and Ofcom and O2 identify Tesco Mobile, giffgaff and Sky Mobile as using the O2 network.
But “same network” does not guarantee the whole experience is identical. Real-world service can still depend on technologies the provider supports, your handset, local capacity and congestion, indoor signal, Wi-Fi Calling support and whether 5G+ is available on your plan. Check the places that actually matter: home, work and regular travel routes.
What is changing on O2’s network in 2026?
O2 is in the middle of a network upgrade. It says it is investing £700 million in 2026 through its Mobile Transformation Plan, including upgraded sites, capacity improvements, new spectrum and expansion of 4G, 5G and 5G+.
O2 has also completed its 3G switch-off. Ofcom confirms Vodafone, EE, Three and O2 have all now completed their UK 3G switch-offs. The next legacy-network change is 2G: Ofcom’s latest guidance says O2 plans to begin switching it off from summer 2029.
Which O2-based provider is best?
For Clubcard users and European roaming
Tesco Mobile is the first one to compare. Clubcard pricing, fixed core pricing on eligible Clubcard Price contracts and Home From Home roaming make it different from O2 itself.
For flexible SIM plans
giffgaff is a strong starting point, with flexible options, 5G, eSIM and up to 5GB of included EU roaming on eligible plans.
For Sky households and data rollover
Sky Mobile makes the most sense when Sky Piggybank is genuinely useful — especially for several family SIMs, Sky services or a compatible handset for 5G+.
The practical order is: check O2 coverage where you use your phone; decide how much data you need; compare live monthly prices; then check roaming, contract length and extras.
The main consumer providers using O2 infrastructure are Tesco Mobile, giffgaff and Sky Mobile. Ofcom lists all three as O2-based providers, and O2 confirms they use its network.
Does Tesco Mobile use O2?
Yes. Tesco Mobile says it is powered by O2’s network, with 4G and 5G service provided over O2 infrastructure.
Does giffgaff use O2?
Yes. giffgaff says directly that its mobile service is powered by the O2 network.
Does Sky Mobile use O2?
Yes. Ofcom lists Sky Mobile as using O2, and O2 names Sky Mobile as a provider running on its network.
Does Virgin Mobile use O2?
Virgin Mobile historically moved onto O2, but it is no longer sold as a standalone service. Virgin Media stopped trading as Virgin Mobile at the end of August 2023 and customers were moved to O2 plans.
Do O2 MVNOs get 5G?
Tesco Mobile, giffgaff and Sky Mobile all currently offer 5G. Sky Mobile also offers O2-based 5G+ on selected compatible devices.
Do O2 MVNOs get the same roaming?
No. Tesco Mobile, giffgaff and Sky Mobile have different roaming terms even though all three use O2 infrastructure.
Which O2-based provider is best for EU roaming?
Tesco Mobile currently has the simplest included-roaming proposition of the three for many travellers because Home From Home covers 48 destinations in the EU and beyond at no extra roaming fee, subject to fair-use terms. Always check the plan before buying.
