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Unlimited data

Best Unlimited-Data SIM Deals — No Data Limits

A straight-talking guide to unlimited-data SIM plans in the UK: what unlimited really means, how fair-use policies work, and when paying for no data cap is actually worth it. Built around the live plans on GetSIMSmart — no invented allowances, speeds or terms.

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What an Unlimited-Data Plan Is

An unlimited-data SIM plan gives you a monthly mobile data allowance with no fixed cap on UK data, alongside unlimited calls and texts. You pay a fixed monthly price and never have to worry about running out of data or paying out-of-bundle rates.

Unlimited does not mean unrestricted, though. Most unlimited plans include a fair-use policy that can slow your speed, restrict tethering or trigger contact above a high monthly threshold. Tethering and roaming are often capped separately. We cover exactly how this works in the fair use section below.

On GetSIMSmart, the live unlimited option is Chattr's plan on the O2 network at £15 a month — a 30-day rolling plan with unlimited data, tethering allowed and 5G included.

Unlimited and High-Data Plans Compared

The live unlimited plan, plus the highest-data capped plans on GetSIMSmart for comparison. Prices are the provider's standard price and can change — confirm on the provider's site before ordering.

1pMobile

EE network

£25/mo

30-day rolling

UnlimitedUnlimited 4G/5GUnlimited data
  • No credit check
  • EU roaming
  • Unlimited UK calls & texts
  • eSIM also available

Chattr

O2 network

£15/mo

30-day rolling

Unlimited4G/5GBest Deal
  • No credit check
  • Unlimited data
  • Unlimited UK calls & texts
  • Tethering allowed

iD Mobile

3 network

£15/mo

30-day rolling

Unlimited4G/5GGOOD VALUE
  • No credit check
  • Unlimited data
  • Unlimited UK calls & texts
  • No annual price rises

iD Mobile

3 network

£10/mo

1-month plan

80GB4G/5GGOOD VALUE
  • No credit check
  • Unlimited UK calls & texts
  • Roaming in 50 destinations
  • No annual price rises
  • 2 Months free Apple subscription

1pMobile

EE network

£10/mo

30-day rolling

50GB4G/5GCheapest big data
  • No credit check
  • EU roaming 50GB
  • Unlimited UK calls & texts
  • eSIM also available

Lyca Mobile

EE network

£5*/mo

pay as you go

* £5/mo for the first 3 months, then £10/mo.

30GB4G/5GNew customer offer
  • No credit check
  • EU roaming 12GB
  • Unlimited UK calls & texts
  • 100 International minutes free
  • eSIM also available

Lebara

Vodafone network

£3.20*/mo

30-day rolling

* £3.20/mo for the first 6 months, then £8/mo. Sign up by Friday 11 December 2026.

30GB4G/5GBest all-rounder
  • No credit check
  • 100 international mins
  • Unlimited UK calls & texts
  • EU roaming 30GB

Links marked as sponsored may earn us a commission. Your price is unaffected.

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Fair Usage and Throttling

Unlimited plans in the UK almost always come with a fair-use policy. Understanding it before you order saves surprises later.

  • A fair-use cap is a monthly ceiling above which a provider may slow your speed, restrict tethering or contact you — even on a plan marketed as unlimited.
  • Tethering and personal hotspot use are often capped separately, so check the tethering allowance if you plan to share your connection with a laptop.
  • Roaming data is almost always capped well below your UK allowance — EU roaming limits on GetSIMSmart plans range from 12GB to 30GB.
  • Plans marketed as unlimited may still restrict use that the provider considers non-personal, such as running a server or reselling data.
  • Speed can be managed during congestion or in busy locations regardless of your plan, which is normal across all UK networks.

The honest summary: unlimited means no fixed UK data cap, not that every conceivable use is unrestricted. Always read the provider's fair-use and tethering terms on their site before ordering.

When Unlimited Is Worth It

Unlimited earns its keep only for genuinely heavy users. If any of these describe you, it is worth the extra cost.

  • You regularly use more than around 50–100GB of mobile data a month.
  • You tether a laptop or tablet frequently and do not want to watch a counter.
  • You use your phone as a substitute for home broadband, for example in a temporary let.
  • You stream a lot of 4K video or large downloads over mobile rather than Wi-Fi.
  • Several people share your hotspot, pushing usage well above a typical single-user plan.

For everyone else, a cheaper capped plan is better value. These are the signs unlimited is probably overkill.

  • You mostly use Wi-Fi at home and work and use under 20GB a month.
  • You want the lowest possible monthly cost — a capped plan is always cheaper.
  • You rarely tether or stream long video over mobile.
  • You are buying for a light user such as an older relative or a child's first phone.

Cheaper High-Data Alternatives

If you use a lot of data but not truly unlimited amounts, a high-data capped plan can save you £5 a month or more with no practical difference to your experience.

1pMobile

50GB · £10/mo

EE, no speed caps, free EU roaming. The most data per pound on the site.

Lyca Mobile

30GB · £10/mo

EE, 100 international minutes, 12GB EU roaming, eSIM available.

Lebara

30GB · £10/mo

Vodafone 5G, 100 international minutes, 30-day rolling.

For most heavy users, 50GB at £10 is the sweet spot — see our guide to SIM-only deals by data usage to find your tier, or the cheapest SIM-only deals guide for the lowest prices.

Frequently Asked Questions

What is an unlimited-data SIM deal?

An unlimited-data SIM plan gives you a monthly data allowance with no fixed cap on UK data usage, alongside unlimited calls and texts. You pay a fixed monthly price and do not have to worry about running out of data — though fair-use and tethering limits may still apply, so read the small print.

Are unlimited-data SIMs really unlimited?

UK data is generally uncapped, but most unlimited plans include a fair-use policy that can slow your speed, restrict tethering or trigger contact above a high monthly threshold. Tethering and roaming are often capped separately. Truly unlimited means no set UK data cap — not that every use is unrestricted. Always check the provider's fair-use terms.

Which unlimited-data plan is on GetSIMSmart?

The live unlimited option on GetSIMSmart is Chattr's plan on the O2 network at £15 a month, with unlimited data, unlimited calls and texts, tethering allowed and 5G included. It is a 30-day rolling plan, so you can cancel any time.

Is unlimited data worth the extra cost?

Only if you regularly use more than around 50–100GB a month — typically from heavy 4K streaming, frequent tethering or using your phone as home broadband. Most people use far less and would save money on a cheaper capped plan such as 1pMobile's 50GB for £10/mo.

Do unlimited-data SIMs require a credit check?

The prepaid and 30-day rolling unlimited plans listed here are not credit agreements and are generally supplied without a hard credit search. A provider may still carry out identity, address or fraud-prevention checks, but these are not credit searches and will not appear on your credit file.

Can I tether with an unlimited-data SIM?

On the live GetSIMSmart unlimited plan (Chattr on O2), tethering is allowed. That said, many unlimited plans elsewhere cap tethering separately from your phone data, so always confirm the tethering allowance on the provider's site before ordering if hotspot use matters to you.

For the full picture across every plan type, read our complete guide to the best SIM-only deals in the UK.

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Unlimited only wins if you actually use the data.

Compare the live unlimited and high-data plans on GetSIMSmart, sorted by allowance.

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