Three information

What it means for you

Three came late to the UK market and never had a voice business to defend, so from the beginning it sold data cheaply and let the rest follow. Two decades on, that is still its personality: aggressive on price per gigabyte, less concerned with reaching every hamlet.

The June 2025 tie-up with Vodafone created the biggest operator in the country by customer count. Nothing changed for existing customers on the day, but a long programme of mast merging began — which is why the coverage picture at any given address is less settled than usual right now.

Two budget names ride these masts. SMARTY is Three’s own; iD Mobile belongs to a high-street retailer. Both sell the same radio waves for less.

What it means for you

Speed is not the problem here — measurement firms have put Three at or near the top for 5G download rates for several years running. Reach is the problem. Thick walls and remote ground are where it thins out, and a coverage map will never tell you that because maps predict signal outdoors.

So do not trust one map. Run Three’s own postcode checker, run Ofcom’s, and lean on the indoor predictions. If they disagree, spend a month on SMARTY — same masts, small money — and live on it properly.

What it means for you

SIM-only. Pick the length by how settled your life is, not by the few pounds between them. Rolling monthly costs a little more and walks away whenever you like — right for a new address, an untested network or a possible move. Fixed terms are cheaper but you must write the end date down.

Handset deals. Three bills the phone and the airtime as one figure. Any offer, however it is dressed up, collapses to one calculation:

Prepaid. No contract, no credit check, no phone finance. Good for a glovebox phone, a first phone for a child, or a month of coverage testing. Once you are using it every week, a rolling SIM from SMARTY or iD costs less.

What it means for you

An eSIM is your plan written into the phone rather than posted on plastic. Same service, faster start, and you can run a second line alongside it — which is what makes it genuinely useful for travel.

Ask for one inside Three’s own app or website. It goes live in minutes.

1. Open the official app — never a link someone sent you.
2. Request the eSIM and follow the on-screen activation.
3. Keep your number by using the ordinary free switching code; digital and plastic are treated identically.
4. For travel, add a cheap local data eSIM and leave your UK line for calls.

What it means for you

A box arrives in the post and you have broadband the same day. No engineer, no digging, no phone line — and no phone line, which matters if somebody in the house still uses one.

The honest trade-off: your speed is whatever the nearest mast can spare. Next to a strong, quiet mast this holds its own against mid-priced fibre. Behind a busy one, evenings sag and nothing you do indoors will fix it.

1. Order inside the returns window so you can send it back for nothing.
2. Stand the router at the window facing the mast — position beats every menu setting.
3. Use it for a full week of real evenings, not one quiet afternoon.
4. Keep it or return it on the evidence.

What it means for you

Which rules apply to you depends on when you signed, not on what the website says today. Your app’s roaming screen is the only version that matters.

Everywhere abroad there is a fair-use ceiling on data. Go past it and per-gigabyte charging starts — and that, not the daily fee you can see, is what produces frightening bills.

1. Read your roaming screen before you book, and write the ceiling down as a number.
2. Check the spend cap is on.
3. Turn off automatic backups and app updates over mobile data.
4. Past a few days away, buy a local data eSIM and keep the UK line for calls.

What it means for you

On the phone, at home, unlimited means unlimited on all four mast owners including this one. Three published conditions bend it, and every one is readable before you sign.

Before buying any allowance, open your current app and read three months of real usage. People routinely buy about twice what they use — over two years that is real money. And two free changes usually remove the need for a bigger tier at all: drop streaming quality one notch, and push backups and updates onto home Wi-Fi.

What it means for you

Three numbers appear on any deal and only one of them describes what you will actually pay.

The free spend cap is the single most useful minute you will spend in the app, and almost nobody uses it. It simply prevents charges beyond your allowance.

What it means for you

Bills go up for five reasons, all of them printed somewhere before you signed:

And they come down for five reasons, none of which happen by themselves:

What it means for you

Three runs a single app that does everything: allowances, bills, spend caps, add-ons, roaming settings, eSIM requests and written chat. Use the written route for anything you might need to prove later, because a phone call leaves no file and a file is what gets reviewed.

1. Install it on day one and set the spend cap while you are in there.
2. Give the account a password you use nowhere else.
3. Switch on every extra protection offered.
4. Only ever install from the official app store.

What it means for you

Most complaints have one of four causes, and two of them are cured by settings that cost nothing.

If the same problem keeps returning, start writing it down — dates, times, what failed — for a fortnight. Then complain in writing with the log attached and ask directly what goodwill applies to the recorded period. Credits get agreed on evidence, not on frustration.

What it means for you

Joining. Check coverage before you look at price. Buy the new plan, text your old network for the code, hand it over, and leave the old SIM in the phone until the number moves — usually the next working day, with no gap.

Leaving. It is two text messages. No conversation is required and none can be demanded.

Your network cannot refuse the code, sit on it, attach conditions, or insist you speak to a retentions team first. Take the offer afterwards if it is good — but take the code first, so you are choosing rather than asking.

If something goes wrong, complain in writing, keep the reference, and escalate free to the Communications Ombudsman at eight weeks or on a final response. Its decision binds the network, not you.