Three information
Britain's cheapest unlimited data, set against its rivals on coverage, price and roaming — then examined in full.
Photo from a free stock library — illustration only.Three
Independent testing repeatedly places Three at or near the top of the UK for 5G speed, and its urban footprint is strong.
- Excellent in built-up areas
- Thinner deep indoors
- Weaker at the far rural edges
- Merger money now aimed at those gaps
EE
The broadest footprint in Britain and more independent test wins than any rival, at a premium price.
- Strongest where rivals thin
- Motorways and market towns
- National lead on standalone 5G
- Still has dead postcodes of its own
EE for reach, Three for speed and price. If you drive for work or live rurally, EE earns the premium. If your week happens in a town and you use a lot of data, Three wins comfortably — provided one cheap month proves the signal in your own rooms.
Three
Has priced unlimited lowest of the four mast owners for several years running, and sells the same signal through SMARTY and iD Mobile for less again.
O2
Unlimited is widely available but rarely the cheapest, and average speeds often trail Three. Its value case rests on roaming and contract structure instead.
Three, clearly, on price per gigabyte. O2 only wins this comparison if you travel to Europe often enough that its roaming policy outweighs the difference.
Three
Most newer plans meter Europe with a daily charge. Some older plans kept inclusive roaming, so your plan's start date decides.
O2
The only one of the four mast owners still including European roaming on standard plans, subject to a published fair-use ceiling.
O2, without much argument. If you cross to Europe several times a year, that single policy can outweigh everything else. Three users can close the gap with a cheap local data eSIM on longer trips.
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Three at a glance
Three entered the UK in 2003 as the first operator built around data rather than voice, and has been half of VodafoneThree since June 2025 — now the largest operator in the country by customer numbers, with a multi-billion-pound mast consolidation under way.
SIM plans
Every commitment length is sold. Which suits you depends far more on how settled your circumstances are than on the price difference.
Size the plan from three months of real usage in the app rather than an estimate. The recorded gap between guess and reality is commonly around a factor of two.
Phone plans
Handset agreements follow the standard bundle: device and airtime combined into one monthly figure over twenty-four to thirty-six months.
The recurring difficulty is the end of term. That figure does not reduce automatically, so device money keeps being collected on a handset you already own — the largest silent overpayment in British mobile.
Pay as you go
Credit-based service with no contract and no credit assessment — useful for spare handsets, children's first phones, temporary lines and coverage testing.
It stops being the cheap option sooner than most people expect. Once use is regular, a rolling monthly plan on the same masts almost always costs less, and prepaid credit can lapse without periodic activity. Read your operator's actual expiry condition rather than the marketing line.
eSIM
Three issues digital SIMs from the app, website or a shop in minutes, across most recent iPhones and Android flagships. Number retention uses the ordinary free PAC text to 65075, and digital and plastic SIMs are identical in law.
The genuinely useful application is travel: keep the Three line for calls and texts, add a cheap local data eSIM at your destination, and route data through it. Past a few days abroad that comfortably beats daily roaming charges.
Home broadband
Three's fixed-address offering is a 4G/5G router delivered by post and working the day it arrives — no engineer, no excavation, no line rental, and no traditional phone line.
Performance is decided entirely by the nearest mast. Beside a strong, uncongested 5G site it competes with mid-priced fibre; behind a busy or distant one, evenings degrade and no in-home setting corrects it.
Treat the returns window as a paid trial: place the router at the window facing the mast, run a full week of real evenings through it, and send it back free if it fails.
Roaming and data
Domestically, unlimited is genuinely unmetered on the handset. Abroad the picture depends on your plan's generation.
Fees, the app and support
One application administers allowances, billing, spend caps, add-ons, roaming settings, eSIM issue and written support. Its most valuable function is evidential: genuine offers appear inside your account, so any cold call can be verified in five seconds.
When it goes wrong
Six adjustments close most reported complaints: Wi-Fi Calling on, 4G Calling on, ten seconds of airplane mode, updates installed, one metre toward a window, then the status page with your postcode.
If a problem repeats, log dates, times, postcode and what failed for a fortnight, then complain in writing and keep the reference.
Your rights, and how to leave
Several protections apply regardless of what any retention script says.
Buy the new plan first, then request the code, then keep the old SIM in until the number lands — usually one working day, with no gap in service.