Most UK adults are paying somewhere between £25 and £45 a month for their mobile contract. Most UK adults could be paying £8-£15 a month for the same network, the same coverage, the same data, on a SIM-only contract from one of the big three networks' own sub-brands. The difference is roughly £200-£400 a year per person, and the only thing standing between most people and that saving is a 30-minute Saturday morning task.
We tested the three best-known mobile MVNOs (mobile virtual network operators) in 2026, Smarty (uses Three's network), iD Mobile (uses Three's network), Voxi (uses Vodafone's network), across two locations for three months. Here is what we learned, including which one to actually switch to.
The verdict, before the detail
| Your priority | Pick |
|---|---|
| Cheapest unlimited data | Smarty (£15/mo unlimited 5G) |
| Best customer service of the three | iD Mobile (UK call centres, on-time response) |
| Heavy social media / streaming user | Voxi (free unlimited social/streaming on top of plan) |
| Frequent international roaming (EU only) | Smarty (best EU roaming inclusion in 2026) |
| Frequent traveller outside EU | None, consider eSIM solutions like Airalo |
If you're with one of the big three (O2, EE, Vodafone, Three direct) and not on a phone contract: switch to Smarty today. There is no good reason to be paying full retail in 2026.
Why MVNOs are usually the right answer in 2026
MVNOs (mobile virtual network operators) lease access to the big networks' physical infrastructure and resell it under different brands, often at much lower prices. They use the same masts, the same 4G/5G coverage, the same base capacity. The difference is the customer service overhead, the brand budget, and the absence of expensive retail stores.
In 2026 UK:
- Smarty runs on Three UK's network
- ID Mobile runs on Three UK's network (different MVNO arrangement)
- Voxi is owned by Vodafone and uses Vodafone's network
- Lebara runs on Vodafone's network
- Giffgaff runs on O2's network
- Tesco Mobile runs on O2's network
If your concern about switching is "the coverage will be worse", it won't, by definition. You're moving to the same physical signal at a cheaper price.
Smarty, the cheapest, the cleanest
Smarty (owned by Three) is the most rigorously priced of the three we tested. £15/month for unlimited 5G data, calls, and texts. No annual price hikes (Smarty contractually doesn't raise mid-contract prices, unlike most big-network providers). 30-day rolling contracts.
What's good:
- £15/month flat for unlimited 5G in 2026 is genuinely the cheapest unlimited mobile.
- Smaller plans go down to £6/mo for 4GB if you don't need unlimited.
- No mid-contract price hikes, in writing, contractually.
- Refunds unused data each month, pro-rated.
- 30-day rolling contracts, leave any time.
- EU roaming included (up to 12GB/month in 2026, post-Brexit equivalent of EU pre-2020).
- App is good. Top up, manage, switch is fast.
What's not good:
- Customer service is online-only. No phone line. For most users this is fine; for users who explicitly want to phone someone, it's not.
- No tethering restriction, actually a positive, but worth noting unlike some networks.
- Three's actual coverage can be thinner than Vodafone or EE in rural areas. If you live somewhere remote, check Three's coverage map at your postcode before switching.
Cost: £6-£15/month depending on plan. Most people want £15/mo unlimited.
Best for: anyone in a Three-strong area who wants the cheapest legitimate unlimited plan.
ID Mobile, the customer-service pick
ID Mobile (owned by Currys/Carphone Warehouse) is the closest the MVNO market gets to mainstream customer service. They run call centres, you can phone them, you can walk into a Currys with an iD complaint. None of the other MVNOs offer that.
What's good:
- Customer service via phone, the only one of the three with this.
- Mid-tier plans (£8-£12/mo for 30-50GB) are extremely competitive.
- Carphone Warehouse / Currys retail support, you can walk into a physical store with an issue.
- Inclusive EU roaming.
- No mid-contract price hikes on most plans (verify at signup).
What's not good:
- Slightly more expensive than Smarty at the unlimited tier.
- Unlimited plan throttles after 200GB/month, fine for most users, not "truly unlimited."
- Three's coverage caveat still applies (iD also runs on Three).
Cost: £8-£20/month depending on plan.
Best for: UK adults who want budget pricing but with the option of a phone call when needed.
Voxi, for social media-heavy users
Voxi (owned by Vodafone) takes a different approach: standard data plan plus endless social media and streaming on top of it that doesn't count against your allowance. WhatsApp, Instagram, TikTok, Snapchat, and several others are zero-rated.
For users who watch hours of TikTok and Instagram every day, this is genuinely useful, a £15/month plan with 30GB plus unlimited social often outperforms a £20/month "unlimited" plan from a competitor that throttles after high-volume usage.
What's good:
- Endless social media and streaming at no cost to your allowance.
- Vodafone's network, better rural coverage than Three in many areas.
- No mid-contract price hikes.
- EU roaming included.
What's not good:
- The "endless" categories are specific. Make sure your usage falls into them. Older platforms or niche apps may not be included.
- Standard data outside the included categories is costed at slightly higher £/GB than Smarty.
Cost: £10-£35/month depending on plan.
Best for: social-media-heavy users on Vodafone-strong coverage.
What we tested
Across three months in two locations (Greater London urban + a Scottish Highland rural test point):
- Coverage maps vs. Actual signal: all three reflected reality reasonably accurately.
- 5G availability: Smarty and iD (Three) had the more aggressive 5G rollout in our urban test; Voxi (Vodafone) had marginally better rural 4G coverage.
- Speed tests: All three averaged 80-200 Mbps download in 5G urban areas. None bottlenecked our usage.
- Calls and texts: indistinguishable from each other.
How to actually switch
This is the easiest 30-minute task in UK consumer life:
- Get a PAC code from your current provider (text "PAC" to 65075, required by Ofcom; takes minutes; works for any mobile carrier).
- Order a free SIM from your chosen MVNO. Smarty / iD / Voxi all post within 1-3 working days.
- When the SIM arrives, follow the activation steps (typically: insert SIM, text "PAC code" to a number, wait 4-24 hours).
- Keep your phone number, the PAC system transfers it automatically.
- Cancel direct debit to your old provider once the switch confirms.
Total time: 30 minutes of your time spread over 1-3 days of waiting for the SIM.
Annual saving: £200-£400.
What works
| Situation | Switch to |
|---|---|
| Currently O2 / EE / Vodafone / Three (off contract, SIM only) | Smarty if you want cheapest, iD if you want phone support, Voxi if you're social-media heavy. |
| Currently on a phone contract | Wait until your contract ends; consider buying the next phone outright on a 0% credit card and using SIM-only afterwards. The lifetime cost is lower. |
| Currently on giffgaff or Tesco Mobile (already MVNO) | Smarty likely cheaper still; check current pricing before switching. |
| Live in a rural area | Check coverage maps before switching. If Vodafone covers your area better than Three, Voxi/Lebara > Smarty/iD. |
The most expensive mobile bill in the in 2026 is the one you're still paying out of inertia.
Affiliate disclosure: Morningfold has affiliate partnerships with several MVNOs. Verdicts were reached on price/feature/coverage testing, see editorial standards.
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