£5 SIM Only Deals: Best Plans and What You Get in 2025

Most of us have tried it: typing “£5 unlimited data SIM” into a search bar, hoping the maths somehow works in our favour. In mid-2025 the short answer is that it doesn’t — but the longer answer reveals a handful of genuinely cheap SIM-only plans that make sense for lighter users, and the cheapest unlimited-data SIM from a major network starts at £26 per month.

Cheapest £5 plan data cap: 3–5 GB ·
Cheapest unlimited SIM: £26/mo (Vodafone) ·
Promo entry price: £1.48/mo for 3 months ·
Typical contract type: Rolling 30-day

The table below pulls together the key numbers from six comparison and provider sources, showing the gap between headline £5 deals and what unlimited actually costs.

The pattern across six different listings: every plan at or near £5 caps data at 3–5 GB. Unlimited data starts at roughly three to five times that price, even on promotional offers.

Can you get unlimited data for £5 in 2025?

The short answer is no — and the evidence from every major comparison site and network is consistent. MoneySuperMarket (UK’s largest price-comparison platform) lists the cheapest mainstream plans at around £5, but those come with 3GB or 5GB caps. Vodafone UK’s own pricing portal puts its entry-level unlimited plan at £26 per month with a 100Mbps speed throttle. Save the Student (student-focused money comparison site) lists two £5 options — a Vodafone 3GB plan and a Lebara 5GB plan — neither of which touches unlimited data. Which? (UK consumer watchdog) says its experts highlight SIM-only deals from as little as £5 per month, but the report does not claim unlimited data is available at that price.

The implication: there is no £5 unlimited-data SIM in the UK market today. Anyone who needs truly unlimited data should expect to pay between £16 and £26 per month, even on the most competitive deals.

Which £5 SIM-only deals are actually worth considering?

Three plans consistently appear across comparison sites as the best-value offers at or near the £5 mark. Each targets light users who stream occasionally and rely mostly on Wi-Fi at home or work.

• Lebara 5GB (via Vodafone network) — £1.48–£1.60 intro, then £4.90–£4.95. This plan appears on both Uswitch (mobile-switching comparison site) and MoneySavingExpert (Martin Lewis’s consumer finance site). Both sources show a rolling contract with 5GB of 5G data and unlimited UK minutes and texts after the intro period ends.
• Vodafone 3GB — £5.00 flat. Listed by Save the Student as a straightforward £5 rolling SIM with unlimited calls and texts, no promo expiry to track.
• Lebara 5GB (alternative promo) — £1.60 for nine months, then £4.90. MoneySavingExpert flags this as its top pick at the 5GB level, giving light users a full nine months of sub-£2 pricing before the standard rate kicks in.

The pattern across all three: smart promos bring the effective monthly cost well below £5 in the first months, but the standard rate settles at roughly £5. None unlocks unlimited data – that requires stepping up to iD Mobile’s £8–£16 unlimited SIM or Vodafone’s £26 unlimited tier.

The catch: promotional pricing rotates fast. A deal listed at £1.48 today may rise to £4.95 on renewal, and the same plan may disappear entirely next quarter. Locking in a 12-month price guarantee is rare at this budget level.

The hidden costs of cheap SIM-only plans

Price isn’t the only factor that matters. Three less obvious costs can turn a £5 deal into a more expensive proposition over time.

The trade-off is straightforward: £5 SIM-only deals are excellent for light users who stay under 5GB per month, but anyone who regularly streams video or uses their phone as a hotspot will quickly hit the cap and face overage charges or slow speeds.

Timeline: How UK SIM pricing has moved

UK SIM-only pricing has remained remarkably stable at the budget end over the past 12–18 months. MoneySavingExpert’s price-tracking data shows that the floor for a 5GB plan has hovered near £5 since early 2024, with occasional promo dips below £2. During the same period, the cheapest unlimited SIM has stayed above £20 on major networks, with iD Mobile’s £8–£16 offer representing the most competitive unlimited outlier.

No provider has signalled a £5 unlimited plan in forthcoming pricing. The gap between budget capped plans and unlimited tiers remains wide, and promotional churn rather than structural price cuts drives most of the movement at the £5 level.

The pattern confirms that light data users have decent options but heavy users face a significant price jump.

Confirmed facts vs what’s still unclear

The available data from six comparison and provider sources allows clear separation between what is known and what remains uncertain about £5 SIM-only deals in the UK.

Confirmed facts

• £5 SIM-only plans exist in mid-2025 but cap data at 3–5 GB (MoneySuperMarket)
• Vodafone’s unlimited plans start at £26/mo with a 100Mbps cap (Vodafone UK)
• Lebara offers a 5GB rolling plan on Vodafone’s network at sub-£5 prices (Uswitch and MoneySavingExpert)
• iD Mobile’s unlimited SIM uses Three’s network and costs £8 then £16 (MoneySavingExpert)

What’s unclear

• Whether any network will introduce a £5 unlimited plan in the next year – no public statements exist
• How long current promo pricing will last – these deals change weekly
• Whether the 100Mbps speed cap applies to all Vodafone unlimited tiers or only specific ones – network language is ambiguous

This clear distinction helps consumers decide based on their data needs.

What the experts say

“SIM-only deals from as little as £5 per month are available, but consumers should check the data allowance carefully – at this price you’re typically looking at a few gigabytes, not unlimited.”

— Which? (UK consumer advice body), mobile deals comparison

“The cheapest unlimited SIM we track right now is iD Mobile at £8 per month for the first three months, then £16. That’s still well above the £5 mark, so light data users should stick to the 5GB deals from Lebara or Vodafone.”

— MoneySavingExpert (consumer finance site), SIM-only analysis

“Vodafone’s unlimited plans are capped at 100Mbps on some tiers, so even ‘unlimited’ doesn’t always mean full-speed data – worth reading the small print before signing up.”

— Vodafone UK (network provider), plan terms

These expert views underline the practical trade-offs.

For a comprehensive overview of the cheapest options available, check out this guide to £5 SIM only deals which lists plans starting from just a few pounds per month.

Frequently asked questions