O2 information
A full information sheet on O2: its history and ownership, the evening congestion issue, split handset contracts, European roaming, costs across a year, and how to switch away.
Sections on this page
The facts
- Started as
- BT Cellnet
- Renamed O2
- 2002
- Owner today
- Virgin Media O2
- Joint venture from
- 2021
- Also sells signal to
- Tesco Mobile, giffgaff, Sky Mobile
- 3G switch-off
- During 2025
What it means for you
This is the oldest lineage in the market, and the biggest landlord in it. Three sizeable consumer brands run on these masts, which means an awful lot of British phones are on O2 radio under a different badge — handy for you, because it makes the signal cheap to test before you commit to anything.
Since 2021 the mobile business has sat alongside a cable company in a joint venture, which is why broadband here means street cabling rather than masts.
The facts
- Footprint
- Broad, nationally
- Known problem
- Evening slowdown in city centres
- Hours affected
- Roughly 5pm to 7pm
- Nature of it
- Capacity, not coverage
- Cheapest way to test
- A month on giffgaff or Tesco Mobile
What it means for you
Coverage is wide and the 5G layer keeps growing. The documented weakness is not about reach at all — it is about how many phones share a mast at once. In busy city centres, roughly between five and seven in the evening, the bars stay full while the data crawls. Independent measurement firms have logged this for years.
That matters because no handset setting fixes congestion, and switching networks only helps if the alternative is less busy at the same spot at the same hour.
- Buy a rolling month on giffgaff or Tesco Mobile — identical masts, small money.
- Go to the place you actually commute through, at about six in the evening.
- Run a video call and a large download, not just a speed test.
- Judge on that, not on the map.
The facts
- SIM-only terms
- Rolling and fixed
- Unlimited
- Widely available
- Handset deals
- Split contract — two agreements
- Prepaid
- Yes
- Perks
- Separate rewards app
What it means for you
Handset deals here are different, and better. The phone and the airtime are two separate agreements, so the device payment genuinely stops when the phone is paid off.
| Part | What happens |
|---|---|
| Device agreement | Its own credit deal; ends at repayment; can be settled early |
| Airtime agreement | Billed separately; can be cut once the device is paid |
| Credit check | On the device half only |
| The trap | Only the device half stops on its own |
SIM-only. Rolling if anything is unproven, fixed if your address and signal are settled. Multi-line discounts exist under one account.
Prepaid. Available, but the brands renting these masts usually beat O2’s own prepaid rates for regular use. Keep prepaid for spare phones, children’s first phones and coverage testing.
The facts
- Supported
- Yes
- Issued by
- App, website or shop
- Time
- Minutes
- Cost
- Nothing, ever
- Two lines
- Possible
What it means for you
- Open the official app — never a link someone sent you.
- Request the eSIM and follow the on-screen activation.
- Keep your number with the ordinary free switching code; digital and plastic are treated identically.
- For travel, add a cheap local data eSIM and leave your UK line for calls.
The facts
- Type
- Cable and full fibre
- Depends on
- Whether your street is wired
- Engineer
- Usually required
- Mast-based
- No
- Bundling
- Household discounts available
What it means for you
Broadband in this group is a fixed-line product — cable or full fibre — and it has nothing whatever to do with your mobile signal. Whether your street is cabled and whether your bedroom gets bars are two unrelated questions.
Bundling mobile and broadband gives real household savings, particularly across several lines. Just do not let a broadband discount push you into accepting weak mobile signal at home; check the two separately and price the household as a whole.
The facts
- Europe
- Still included on standard plans
- Unique among
- The four mast owners
- Ceiling
- Published fair-use limit
- Beyond it
- Per-gigabyte charging
- At sea
- Outside all protection
What it means for you
This is the genuine selling point. O2 is the only one of the four mast owners still including European roaming on standard plans rather than charging a daily fee.
It is included up to a published fair-use ceiling. Past that, per-gigabyte charging begins — which is where surprise bills actually come from, not from any visible daily charge.
- Read your roaming screen before you book, and write the ceiling down as a number.
- Check the spend cap is on.
- Turn off automatic backups and app updates over mobile data.
- Past a few days away, buy a local data eSIM and keep the UK line for calls.
The facts
- Unlimited at home
- Genuinely unmetered
- Tethering
- Capped on some plan generations
- Very heavy users
- Briefly queued at busy masts
- Abroad
- Ceiling, then per-GB
- Typical over-buying
- Around double
What it means for you
On the phone, at home, unlimited means unlimited on all four mast owners. Three published conditions bend it, and every one is readable before you sign.
| Condition | What it actually does |
|---|---|
| Tethering cap | Limits sharing data with a laptop on some plan generations |
| Traffic management | Queues extreme outliers at saturated masts; normal heavy use never notices |
| Fair use abroad | Ends the unlimited part at a published figure |
Before buying any allowance, read three months of real usage in your current app. People routinely buy about twice what they use. Two free changes usually remove the need for a bigger tier: drop streaming quality one notch, and push backups and updates onto home Wi-Fi.
The facts
- Statement shows
- Two figures, not one
- Real airtime price
- After any discount
- Device charge
- Ends at repayment
- Yearly figure
- Both lines × 12
- Spend cap
- Free, one minute
What it means for you
Because the contract is split, the maths is easier here than anywhere — but only if you look at both lines.
| Figure | What to make of it |
|---|---|
| Airtime charge | Judge it after any discount ends; this is your real ongoing price |
| Device charge | Temporary by design; settle it early if you want it gone |
| Combined total | Tells you almost nothing on its own |
| Whole-term cost | Deposit + (both lines × months) |
| Yearly cost | Useful for budgeting, and rarely offered unprompted |
The facts
- Mid-term rises
- Stated in pounds and pence before signing
- Rule since
- January 2025
- Most common rise
- A discount quietly ending
- Falls
- Only when you act
- Escalation
- Free at eight weeks
What it means for you
Bills go up for five reasons, all of them printed before you signed:
| Reason | Behind it |
|---|---|
| A mid-term increase | Disclosed in pounds and pence at the point of sale since January 2025 |
| The introductory discount ending | Its length was stated when you bought |
| Going past your allowance | Only possible if no spend cap was set |
| A minimum term ending | Not a rise — a fall that did not happen |
| An add-on renewing | One-off purchases sometimes repeat |
And down for five, none of which happen by themselves:
| Move | Effect |
|---|---|
| Switch to SIM-only when the term ends | Strips out the phone payment |
| Cut the allowance | If three months of usage says the tier is too big |
| Buy a one-off add-on instead of upgrading | Covers one heavy month without repricing the year |
| Haggle with rival quotes in hand | Get the PAC first, so you are choosing rather than asking |
| Leave | The exit cost is itemised before you commit |
One saving is unique to this network’s structure: cut the airtime the moment the device agreement finishes. Nothing does it for you, and nobody will remind you.
The facts
- Number of apps
- Two — account and rewards
- Shared login
- Yes
- That login also guards
- The number your bank texts
- Written support
- Yes
- Genuine offers appear
- Only inside the app
What it means for you
There are two apps here, one for the account and one for the rewards platform, and they share a single login. That makes the password unusually valuable to a criminal, because the same login sits behind the phone number your bank sends codes to.
- Install it on day one and set the spend cap while you are in there.
- Give the account a password you use nowhere else.
- Switch on every extra protection offered.
- Only ever install from the official app store.
The facts
- First fix
- Wi-Fi Calling
- Second fix
- 4G Calling
- Then
- Ten seconds of airplane mode
- Then
- Status page by postcode
- If it repeats
- Two weeks of written records
What it means for you
| What you see | Usually | Fix |
|---|---|---|
| An older phone dropping calls | 3G has been switched off nationally | Turn on 4G Calling; if the phone cannot, it is finished |
| One room always bad | Building materials blocking radio | Turn on Wi-Fi Calling |
| Full bars, nothing loads | Too many phones on one mast | Nothing on the handset helps |
| Whole street out for hours | Mast work or a local fault | Check the status page by postcode |
If the same problem keeps returning, write it down for a fortnight — dates, times, what failed — then complain in writing with the log attached and ask what goodwill applies to the recorded period. Credits get agreed on evidence.
One caveat specific to this network: the early-evening slowdown in busy centres is congestion, not a fault, so support cannot fix it. Testing another network at the same place and hour is the only way to know whether moving would help.
The facts
- Keep your number
- Text PAC to 65075
- Give it up
- Text STAC to 75075
- Cost
- Free
- Code valid
- 30 days
- Transfer time
- Usually one working day
- Escalation
- Free at eight weeks
What it means for you
Joining. Check coverage before price. Buy the new plan, text your old network for the code, hand it over, and leave the old SIM in until the number moves — usually the next working day, with no gap.
Leaving. Two text messages. No conversation is required and none can be demanded.
| Text | To | Result |
|---|---|---|
| PAC | 65075 | Your number moves to the new network |
| STAC | 75075 | Account closes, number given up |
| The reply | — | Lists any exit charge and phone balance before you commit |
Your network cannot refuse the code, sit on it, attach conditions, or insist you speak to retentions first. Complain in writing if it goes wrong, keep the reference, and escalate free to the Communications Ombudsman at eight weeks or on a final response.
If you are actually with Tesco Mobile, giffgaff or Sky Mobile, all of this — complaints included — goes to that brand and never to O2.
Works well for
- Anyone travelling to Europe more than once or twice a year
- People who want a phone deal they can audit line by line
- Households who will use the rewards platform
- Anyone wanting to test a big network cheaply first
- People in areas with no mast coverage, thanks to satellite trials
Works badly for
- Heavy commuters into congested city centres who cannot test first
- People chasing the fastest average speeds
- Anyone who reads only the combined total on a bill
- Prepaid users, who will do better on the budget brands
- Anyone whose street has no cable, if broadband matters
In one line: the best roaming terms of the big four and the clearest contract structure — spoiled slightly by rush hour in the biggest cities.
Still unsure after reading this?
Ring the desk and we will go through it with you. There is nothing to buy at any stage.