Three Business Mobiles

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Three’s cheapest business SIM is £11 a month excluding VAT for 3GB on a 24-month term, with unlimited minutes and texts. Its most expensive is £29 for unlimited data on a one-month rolling term. There are fifteen plans in the grid, and not one of them has a price on Three’s business SIM page.

We checked all fifteen tiles. Every one shows “Contact us to buy” or “Buy now” and an “Increasing to:” field left blank. The only number on the page is a banner saying single SIMs start “from just £9 a month”, which does not correspond to any plan in the grid.

The prices do exist. They are in Three’s own Business Price Guide, a PDF effective 21 May 2026, and that is where every figure on this page comes from. If you are getting quotes, this is the table to have in front of you before you ring them.

The actual published prices, all excluding VAT

From Three’s Business Price Guide, for customers who joined, upgraded or added services on or after 1 December 2023. Unlimited minutes and texts on every plan.

Add 20% VAT if you cannot reclaim it: the 24-month unlimited plan is £22 ex-VAT and £26.40 inclusive. Three states plainly that “all prices in this Price Guide exclude VAT where applicable”, and it quotes its advertised savings the same way.

Two things about those figures are worth pausing on. The 1-month rate for 3GB is £18 against £11 on 24 months — you pay a 64% premium for flexibility on the smallest plan, which is the steepest flexibility penalty in the grid. And the jump from 80GB to 500GB on 24 months is £4, from £15 to £19, which makes the mid-tier plans poor value: 80GB costs £15 and more than six times the data costs £19.

The headline prices also include a £5 monthly discount for paying by a recurring method such as Direct Debit. Pay any other way and every figure above goes up by £5.

The annual rise is a fixed amount, and the band you land in matters

Three’s business contracts rise every April by a fixed amount rather than by an inflation index, and the amount depends on which price band your plan sits in. All figures exclude VAT:

• Monthly charge of £9.99 or less — rises by £0.50
• £10 to £20 — rises by £0.75
• £20.01 and above — rises by £1.50

The bands create a cliff edge. A plan at £20.00 rises by 75p; a plan at £20.01 rises by £1.50, double the increase for one extra penny of monthly charge. Over a 24-month contract with two April rises, the difference is £18 per SIM.

Three Business Adapt and Dynamic are carved out of the fixed amounts and rise by 4.5% instead. Adapt is the route Three pushes businesses towards once you have 50 or more connections, so the larger you are, the more your increase tracks a percentage of a bigger bill.

The cancellation fee is harsher than the consumer one

This is the clause most worth knowing before signing, and it is a genuine difference between Three’s business and consumer contracts.

On a consumer contract, the fee for leaving early is the remaining monthly charges “less a variable discount, currently 3%”. Three’s own worked example: £25 a month with six months left is £150, minus £4.50, so £145.50.

On a business contract there is no such discount. The fee is “a lump sum equivalent to the total of the applicable Monthly Charges” remaining in the minimum term, and Three’s business worked example is the same £25 over six months at a flat £150. You pay the full remaining balance.

And it is charged per line. The price guide states that each SIM may carry its own cancellation fee. On a fleet of ten SIMs at £22 a month with a year left, that is £2,640 ex-VAT to walk away. Price the exit before you price the plan.

Shared data across the account, and the add-on nobody can read

Three’s most useful business feature is account-level shared data. You buy an allowance at billing-account level and it applies to every connection under that account, whatever individual plan each line is on. Sizes run from 30GB to 50TB.

The prices are published as two lists — one-off add-ons at £24, £80, £200, £400 and £760, and recurring ones at £21, £70, £175, £350 and £665. What is not published is which price buys which allowance. The table’s columns do not line up in Three’s own PDF, and the guide itself tells you to ring 337 to find out.

One important restriction: “recurring add-on allowances cannot be rolled over”. Unused shared data does not carry into the next month, so buying headroom for a busy quarter means paying for it in the quiet ones too.

Out of allowance, business data is 1p per MB ex-VAT, which works out at roughly £10 a GB. A single employee tethering a laptop for an afternoon can clear the price of their whole monthly plan.

Is the network actually any good? Ofcom's own answer

Three makes two claims on its business pages — “UK’s Fastest 5G Network” and “award-winning” — and publishes no basis for either on the page itself. Ofcom’s own measurement is more useful, and it is good news for Three.

In Ofcom’s Mobile Matters 2025, published 17 July 2025 on data to March 2025:

• “Three’s download speeds tended to be faster than the other MNOs’ on 5G.”
• 10MB file download times over 5G ranged from 0.8 seconds for Three to 1.4 seconds for EE — Three was fastest.
• Three had the highest share of 5G connections at 50 Mbit/s or above, at 75%.
• Three had the best 5G latency, with operator averages spanning 15 to 21 milliseconds.

On complaints, Ofcom’s Q1 2026 figures put Three at 2 complaints per 100,000 pay-monthly subscribers — exactly the industry average, level with Tesco Mobile, better than Sky Mobile on 4 and O2 and iD Mobile on 3, behind EE, Giffgaff and Vodafone on 1 each.

Coverage, in Three’s own words: the combined 4G and 5G network covers 99% of the outdoor population, with 4,700 5G sites across 650 towns and cities. Three has switched off its 3G network entirely, so older handsets and some payment terminals will not fall back to it. Ofcom’s Connected Nations 2025 adds one qualifier worth knowing: “Three does not currently deploy 5G SA services” — standalone 5G.

Where it falls short for a business buyer

You cannot shop without talking to someone. Fifteen plan tiles, no prices, “Contact us to buy”. For a small business comparing three networks on a Tuesday afternoon, that is a real cost in time, and it is a choice Three has made rather than a technical limitation — the prices are published in a PDF two clicks away.

No published limit on connections, in either direction. We could find no stated minimum or maximum in the business terms or the price guide. The multibuy discount covers “up to 9 SIMs”, teams of 50+ get routed to Three Business Adapt, and Three Mobile Protect “covers up to 25 devices” — but none of those is a contractual limit on how many lines you can hold.

No international calling bundle is published at all. For a business making regular overseas calls that is a significant gap in the published information; the pages link to “Calling abroad” without naming a product or a price.

Device management is listed without detail. Three Device Management, Three Mobile Protect and Three Analyst all appear as names with no pricing and no specification, and Mobile Protect stops at 25 devices, beyond which it is “a separate service” that is also unpriced.

One advertised price does not add up. Three’s business homepage shows an unlimited data SIM at “£17 a month, rising to £17.75 from April 2026 and £28.50 from April 2027”. A £10.75 step in year two is seven times the published £1.50 band increase, so it is almost certainly a promotional price expiring rather than an annual rise — but Three presents it as the rise. Read any Three business quote for the year-two and year-three numbers, not just the headline.

Who owns Three now, and why it matters to a business contract

The company you contract with is Hutchison 3G UK Limited, company number 03885486, registered at 450 Longwater Avenue, Green Park, Reading RG2 6GF, incorporated 29 November 1999.

It is no longer independent. Three’s merger with Vodafone completed on 31 May 2025, creating VodafoneThree, initially 51% Vodafone and 49% CK Hutchison. On 5 May 2026 Vodafone agreed to buy out the remaining 49% for £4.3 billion, with completion expected in the second half of 2026 subject to National Security and Investment Act approval. Vodafone says there will be “no change to VodafoneThree’s multi-brand strategy”, so Three continues to sell as Three.

For a business signing a 24-month contract, the relevant detail is that the CMA cleared the merger on 5 December 2024 subject to legally binding commitments, with final undertakings accepted on 28 March 2025. The network must be built out over eight years from completion, and Ofcom has primary responsibility for monitoring it, with quarterly meetings for the duration. VodafoneThree has committed £11 billion of investment — a figure it states itself, over “the next 10 years” in one place and “by 2034” in another. The CMA’s own undertakings say only “invest billions”, so treat £11bn as the company’s commitment rather than a regulator-enforced one.

Figures were taken from each provider's own published terms on 8 October 2026. Variable rates can change at any time — confirm the current rate with the provider before applying.