Cheap mobile brands are not separate networks. They rent space on one of the four that own the masts, and they pass part of the saving on to you. Ofcom’s 2026 pricing report found that the largest operators’ main brands tend to cost more than smaller providers for SIM only plans. This guide shows who is behind the main budget brands, what the tests say about speed, and what to check before you sign up.
Who uses which signal
| Brand | Uses | Who is behind it | Worth knowing |
|---|---|---|---|
| giffgaff | O2 | Owned by Virgin Media O2’s parent company | EU roaming included, with a 5GB monthly limit |
| Tesco Mobile | O2 | Tesco | One of the highest scores for satisfaction in Ofcom’s customer service research |
| Sky Mobile | O2 | Sky | Most complained about for pay monthly mobile in January to March 2026, mainly by people trying to leave |
| Smarty | Three | Owned by Three | Rolling plans, EU roaming with a 12GB monthly limit |
| iD Mobile | Three | Independent brand | EU roaming with a 30GB monthly limit |
| Lebara | Vodafone | Independent brand | EU roaming with a 30GB monthly limit, plus India and calls to many countries |
| VOXI | Vodafone | Owned by Vodafone | Unlimited social media on its plans. EU roaming needs a pass from £2.45 a day. |
| Talkmobile | Vodafone | Owned by Vodafone | Rolling and 12 month plans |
| BT Mobile | EE | BT | Brought back in 2026 for BT broadband customers only |
| Monzo Mobile | O2 | Monzo | A newer eSIM only brand, covered in the FAQs |
Ofcom publishes the official list of which brand uses which network next to its coverage checker. Brands can change host, so confirm before you order. Our guide to the test results behind each host network shows how the four compare.
Why they cost less
Ofcom’s earlier research found that budget operators had the lowest SIM only prices for most of the period it studied, and that none of the larger networks was the cheapest. These brands often keep their plans simple, with fewer extras and fewer shops. Several say they hold prices through the year, so look at which plans hold their price before you decide. Do not assume every plan does, because it depends on the deal.
What you may give up
Opensignal compared independent brands with the four networks between November 2024 and January 2025. In the UK, networks averaged 39.2Mbps and independent brands 33.8Mbps for download speed. Reliability scored 866 for the networks and 856 for the brands, out of 1,000. The gap is small, and it was smaller in the UK than in the other six countries tested.
Opensignal suggested several reasons. The networks may give their own customers priority when a mast is busy, some brands cap speeds, some have limited access to network features, and phones differ between groups. In practice:
- Speed may drop at busy times and places, such as events and crowded stations.
- Some plans cap download speed. Read the terms.
- Some features may be missing on some plans, so check eSIM, 5G and Wi-Fi calling for the plan you want.
- Roaming limits are tighter on some brands.
That study left out brands owned by the networks, so it says little about giffgaff, Smarty, VOXI or Talkmobile.
Service and complaints
Ofcom’s 2025 customer service report, using 2024 data, found giffgaff and Tesco Mobile customers the most satisfied, both at 94%. O2 and Vodafone customers were below average, at 85% and 84%. Tesco Mobile had the fewest complaints to Ofcom, at 4 per 100,000 customers, against 23 for O2. For handling complaints, Tesco Mobile scored 68% and Three 51%. These figures can change each year, so use them as a guide rather than a promise.
Roaming limits compared
| Brand | EU roaming | Monthly limit |
|---|---|---|
| giffgaff | Included | 5GB |
| Smarty | Included | 12GB |
| iD Mobile | Included | 30GB |
| Lebara | Included | 30GB |
| VOXI | Pass needed | 20GB |
Limits and terms change, so check them before you travel. Our guide to EU roaming limits explained covers what happens past the cap.
Checks before you choose
- Confirm which network the brand uses, then try confirming signal for a low cost SIM at your home and work postcode.
- Choose a plan you can leave. See no contract and rolling options if you want to try a brand first.
- Look at what to check on a SIM only deal for allowances, contract length and extras.
- Check roaming and speed caps if you travel or stream a lot.
- Keep your number by moving to a budget brand with your number.
Where to go next
Compare cheapest plans by monthly cost and then filter by the host network you have chosen.
FAQs
Are new brands such as Monzo Mobile worth a look?
Monzo Mobile is an eSIM only plan on the O2 network, run through the Monzo app. It has three plans with no long contracts and needs a Monzo current account. It is new, so read the terms and check availability before you rely on it.
Is a brand owned by a network the same as the network?
Not quite. Brands such as Smarty, VOXI and Talkmobile are owned by the network that carries them, so they are often closer to it than a retailer brand is. They still sell different plans and may handle priority differently.
Do cheap brands offer 5G and Wi-Fi calling?
Many do, but it varies by plan. giffgaff, for example, says all its plans include 5G. Check the plan page for 5G, Wi-Fi calling and eSIM before you order.