The four networks, in the latest tests
RootMetrics drives and walks test routes across the UK twice a year. In its first-half 2026 study, reported by ISPreview in August 2026, EE came first overall and topped or shared the top spot in every category.
| Network | RootMetrics overall score, H1 2026 | Median download speed | Cheaper brands that use it |
|---|---|---|---|
| EE | 95.6 | 130.3 Mbps | BT Mobile |
| Three | 89.5 | 48.1 Mbps | Smarty, iD Mobile |
| Vodafone | 88.4 | 54.0 Mbps | Voxi, Lebara |
| O2 | 84.1 | 54.7 Mbps | giffgaff, Tesco Mobile, Sky Mobile |
Vodafone and Three merged in 2025 into one company, VodafoneThree, but are still sold as two brands and were tested separately. Other testers, such as Opensignal, measure from people's own phones and split some awards differently, so no network wins everywhere.
What matters more than the league table
- Signal where you actually are. A national score says nothing about your street, your office or your train. Ofcom's coverage checker shows each network's signal by postcode, indoors and outdoors.
- The brand, not only the network. A cheaper brand on the same network usually gets the same signal for less money. Speeds can be capped on some, and customer service differs.
- Price rises. Since January 2025 Ofcom requires any price rise built into a contract to be stated in pounds and pence when you sign, instead of a percentage linked to inflation. Read that line before you agree.
- Calling Bangladesh. If you call home often, compare the international minutes in each plan. Some cheaper brands include minutes to Bangladesh; on others every call is charged.
- Roaming. Charges for using your phone in Europe came back after Brexit on several networks. Check the plan if you travel.
Which should you choose?
- If signal and speed matter most, especially outside cities: EE, or BT Mobile for the same network at a different price.
- If price matters most: a cheaper brand on whichever network the coverage checker shows is strong at your postcode.
- If you are new to the UK and have no credit history: a SIM-only plan on a 30-day rolling contract or pay as you go, which usually needs no credit check. See SIM-only or a phone contract.
Questions people ask
Which is the best mobile network in the UK?
In RootMetrics' first-half 2026 study, EE came first overall, followed by Three, Vodafone and O2. The best network for you is the one with the strongest signal at your own postcode, which Ofcom's coverage checker shows.
Is giffgaff on the same network as O2?
Yes. giffgaff, Tesco Mobile and Sky Mobile use the O2 network, so where O2 has signal they do too.
Are Vodafone and Three the same company now?
Yes. They merged in 2025 to form VodafoneThree, but both brands are still sold separately.