Finding the right SIM-only plan in the UK has become one of the most effective ways to cut monthly mobile costs without sacrificing data, coverage, or features. With dozens of deals from both major networks and smaller MVNOs, the options range from promotional offers under £2 a month to all-you-can-use data plans that rival traditional contracts. The challenge is picking the one that fits your usage, contract preference, and whether you need roaming included.
The market has shifted noticeably in 2025. Unlimited data plans have dropped below £20 for the first time on several networks, while roaming policies have become a key differentiator following post-Brexit adjustments. According to comparison sites such as MoneySuperMarket and MoneySavingExpert, the cheapest headline deals now start at roughly £1–£5 a month on rolling contracts, though these are often promotional rates that rise after a few months.
This article compares the main contenders — EE, O2, Vodafone, Lebara, iD Mobile, and Tesco Mobile — across price, data allowances, contract lengths, and roaming. It also covers what Martin Lewis and his team at MoneySavingExpert recommend, how SIM-only stacks up against handset contracts, and which details remain uncertain.
What is the best SIM only deal in the UK right now?
Lebara
£1.48/month (3 months) then £4.95/month
5GB data, rolling contract
EU roaming in 37 destinations included
iD Mobile
£8/month (3 months) then £16/month
Unlimited data, 24-month contract
Equivalent £11.59/month over 12 months
O2
£23/month unlimited data
Europe Zone roaming included
25GB fair-use allowance
Spusu
£3.90/month
3GB data, 1-month contract
Runs on EE’s network
- SIM-only plans are typically 30–60% cheaper than equivalent handset contracts over 24 months, according to comparison site data.
- Unlimited data plans have become more competitive in 2025, with several networks offering sub-£20 deals on 12-month contracts.
- Martin Lewis consistently recommends checking 30-day rolling deals first to avoid locking in if prices drop further.
- Roaming policies vary widely — Lebara and iD Mobile often include EU roaming, while others may charge extra or have daily caps.
- The cheapest deals frequently come from MVNOs such as Lebara, iD Mobile, and Lyca, which operate on major networks but may have slower data speeds or fewer perks.
- Introductory promotional rates can be significantly lower than standard prices, so the long-term cost matters more than the headline figure.
- Network ownership matters: Lebara uses Vodafone’s infrastructure, Spusu runs on EE, and ASDA Mobile uses Vodafone, which affects coverage and speeds.
| Network | Plan | Intro Price | Standard Price | Data | Contract | Roaming | Note |
|---|---|---|---|---|---|---|---|
| Lebara | 5GB rolling | £1.48/mo (3 months) | £4.95/mo | 5GB | Rolling | 5GB in 37 destinations | Best for light users |
| iD Mobile | 25GB 1-month | £6/mo | £6/mo | 25GB | 1 month | Plan-dependent | Good mid-tier value |
| iD Mobile | Unlimited | £8/mo (3 months) | £16/mo | Unlimited | 24 months | Plan-dependent | Cheapest unlimited |
| Tesco Mobile | Selected contracts | Not visible | Varies | Varies | Varies | Home from Home (48+6 destinations, 12GB) | Clubcard perks available |
| O2 | Unlimited Classic | £23/mo | £23/mo | Unlimited | 24 months | Europe Zone inc. (25GB fair use) | Strong roaming inclusion |
| O2 | 100GB | £19.99/mo | £19.99/mo | 100GB | 24 months | Europe Zone inc. | Good for heavy users |
| Vodafone | Unlimited with Euro roaming | £26/mo | £28.50 (2027) / £31 (2028) | Unlimited | 24 months | Euro roaming included | Price rises built in |
| EE | EU Roam Pass | £2.72/day or £16.50/7 days | N/A | Varies by plan | N/A | 47 destinations, 50GB fair use | Add-on pass model |
| Spusu | 3GB 1-month | £3.90/mo | £3.90/mo | 3GB | 1 month | Not specified | Uses EE network |
| Talkmobile | 5GB 1-month | £4.95/mo | £4.95/mo | 5GB | 1 month | EU roaming included | Good value with roaming |
| ASDA Mobile | 3GB 12-month | £5/mo | £5/mo | 3GB | 12 months | Not specified | Uses Vodafone network |
Which SIM only deals offer unlimited data?
Unlimited data plans have seen the most competitive pricing shifts in 2025. The cheapest unlimited option visible in comparison results comes from iD Mobile, which offers unlimited data at £8 a month for the first three months and £16 a month thereafter on a 24-month contract. MoneySavingExpert quotes an equivalent monthly cost of roughly £11.59 when spread over 12 months after accounting for voucher value.
How much does unlimited data cost across networks?
O2 offers an Unlimited Classic plan at £23 a month on a 24-month contract, with Europe Zone roaming included. Vodafone’s unlimited plan with Euro roaming starts at £26 a month but includes built-in price increases — rising to £28.50 in 2027 and £31 in 2028, according to the Vodafone deals page. Tesco Mobile also offers unlimited data on selected SIM-only contracts, though specific pricing was not visible in the available snippets.
Unlimited data plans often include a fair-use policy. According to Uswitch, some networks may throttle speeds after a certain threshold — for example, 100GB — even on plans advertised as unlimited. The exact limits vary by provider and are not always clearly stated at the point of sale.
Which unlimited plan offers the best value?
Based on the available data, iD Mobile provides the lowest headline price for unlimited data, though the 24-month lock-in and post-promotional jump to £16 should be factored into the total cost. O2’s unlimited plan is more expensive per month but includes European roaming without an extra fee, which can make it better value for frequent travellers. If you are also looking at phones, compare the best mobile phone deals with handset to see the full picture.
What are the best SIM only deals with roaming included?
Roaming policies have become one of the most important differentiating factors between SIM-only deals in 2025. The approach varies significantly: some networks include EU roaming as standard, while others charge a daily or weekly pass.
Which networks include free EU roaming?
O2 includes Europe Zone roaming on its pay-monthly plans with a 25GB fair-use allowance, according to Uswitch’s roaming guide. Tesco Mobile offers Home from Home roaming across 48 Europe Zone destinations plus six additional countries, with a 12GB fair-use limit. Vodafone includes Euro roaming on new pay-monthly plans under its Roam Further feature.
Which networks charge extra for roaming?
EE uses an add-on pass model. Travellers can purchase an EU Roam Pass at £2.72 per day or £16.50 for seven days, which covers 47 destinations with a 50GB fair-use cap. Lebara includes up to 5GB of roaming in 37 destinations on its cheapest 5GB deal, making it a strong option for light roamers. iD Mobile’s roaming allowances are plan-dependent and generally considered less generous than O2 or Tesco Mobile, according to the Uswitch roaming guide.
Roaming allowances can be structured as a data cap within your plan or as a separate add-on. For example, Lebara’s 5GB deal includes up to 5GB of roaming in 37 destinations, while O2’s unlimited plan has a 25GB fair-use limit specifically for roaming. Always verify whether the allowance is a hard cap or a fair-use threshold.
What are the best SIM only deals from EE, O2 and Lebara?
EE SIM only deals
EE’s SIM-only offering is built around its network reputation for speed and coverage. The provider uses an add-on model for roaming via the EU Roam Pass, priced at £2.72 per day or £16.50 for seven days, covering 47 destinations with a 50GB fair-use policy. Specific plan prices were not visible in the available snippets, but EE typically positions itself as a premium option. For those who prioritise network performance and are willing to pay extra for roaming, EE remains a contender.
O2 SIM only deals
O2 offers a 100GB plan at £19.99 a month on a 24-month contract, and an Unlimited Classic plan at £23 a month, also on a 24-month term. Both include Europe Zone roaming with a 25GB fair-use allowance. O2’s plans are more expensive than the cheapest MVNO deals, but the included roaming can offset the difference for regular travellers.
Lebara SIM only deals
Lebara consistently appears as one of the best-value options in comparison results. Its cheapest visible deal is £1.48 a month for three months, then £4.95 a month for 5GB on a rolling contract, with up to 5GB of roaming in 37 destinations. MoneySavingExpert’s 2025 analysis describes Lebara as the top value for light-to-moderate users, particularly during promotional periods. The network runs on Vodafone’s infrastructure.
Many of the cheapest deals, including Lebara’s £1.48 offer, are introductory rates that last only three months. After the promotional period ends, the price rises to the standard rate — in Lebara’s case, £4.95 a month. Always calculate the total cost over 12 or 24 months to compare plans fairly.
How do SIM only deals compare to traditional contracts?
SIM-only plans are generally 50–70% cheaper than equivalent handset contracts because you pay only for the service, not the phone. Over 24 months, the savings can amount to several hundred pounds. The trade-off is that you need to own a handset outright or have paid off an existing contract. If you are also looking at phones, compare the best mobile phone deals with handset to see the full picture.
Contract length is another factor. Thirty-day rolling deals offer maximum flexibility but often come with higher standard prices or fewer perks. Twelve-month and 24-month plans typically lock in a lower monthly rate but commit you for longer. Martin Lewis recommends starting with a 30-day deal to avoid being locked in if prices drop further.
You can keep your current number when switching to a SIM-only deal by requesting a PAC code from your existing network. The number can then be transferred within 24 hours. This process is free and regulated by Ofcom.
How have SIM only deals evolved from 2020 to 2025?
- 2020: The COVID-19 pandemic accelerated the shift toward flexible contracts. Thirty-day SIM-only plans became mainstream as consumers sought to reduce fixed costs.
- 2021: 5G SIM-only plans launched from EE, Vodafone, and Three, making next-generation speeds accessible without a handset contract.
- 2022: Ofcom introduced rules to prevent inflation-linked mid-contract price rises on new contracts, effective from 2023, giving consumers more predictable costs.
- 2023: Unlimited data plans dropped below £20 a month for the first time, with iD Mobile among the networks leading the price reduction.
- 2024: More MVNOs began offering 100GB+ plans for under £10 a month. Martin Lewis and his team at MoneySavingExpert selected Lebara as the top-value option for light users.
- 2025: Post-Brexit roaming policies continue to evolve, with some networks reintroducing or expanding EU roaming offers. Competition has pushed the cheapest promotional deals below £1.50 a month.
What is certain and what remains unclear about SIM only deals?
| Confirmed information | Uncertain or variable details |
|---|---|
| Current intro prices for top deals are publicly listed on comparison sites and provider pages. | Standard price after the intro period may change — always check the full terms before signing. |
| Contract lengths and cooling-off periods are clearly stated in each plan’s terms. | Actual 5G speeds depend on location, network congestion, and device capability. |
| Network ownership is public knowledge — for example, Lebara uses Vodafone’s infrastructure. | Roaming fair-use policy details and potential throttling thresholds are not always clearly explained. |
| Ofcom regulations protect consumers from unexpected mid-contract price hikes tied to inflation. | Specific plan availability at the time of user visit may differ from published comparisons — plans change frequently. |
Why are SIM only deals growing in popularity in the UK?
Several factors are driving the shift toward SIM-only plans. The rise of eSIM technology has made switching between providers easier, while longer phone lifecycles mean many users are happy to keep their handsets for three or four years. The cost-of-living crisis has also pushed consumers to look for ways to reduce monthly outgoings, and SIM-only deals offer a straightforward saving compared to traditional contracts.
Network competition has played a major role in driving prices down. MVNOs such as Lebara, iD Mobile, and Spusu have introduced aggressive pricing that forces the major networks to respond. Ofcom’s 2022 ruling on mid-contract price rises added another layer of consumer protection, making SIM-only plans more predictable and trustworthy.
Martin Lewis and the MoneySavingExpert team have been influential in shaping consumer choices. Their regular deal updates and methodology explain not just which plans are cheapest, but which offer the best overall value when factoring in roaming, contract flexibility, and network quality.
Which sources can you trust for SIM only deal comparisons?
Comparison sites such as Uswitch and MoneySavingExpert provide regularly updated tables with filterable options. MoneySavingExpert’s guides are particularly valued for their editorial independence and methodology. Official network pages — including those from EE, O2, Vodafone, Lebara, and Tesco Mobile — offer the most authoritative pricing but lack the cross-market perspective of independent comparison tools.
“If you’re out of contract and happy with your phone, switching to a SIM only deal is the easiest way to save £100s a year.”
— MoneySavingExpert.com (Martin Lewis team)
“SIM only plans are often the cheapest way to get unlimited data, but check the fair usage policy – some networks throttle after 100GB.”
— Uswitch editorial team
“Lebara consistently offers the best value for light-to-moderate users, especially during promotional periods.”
— MoneySavingExpert.com (2025 analysis)
What should you consider when choosing a SIM only deal?
The right SIM-only deal depends on your data usage, whether you need roaming, and how much contract flexibility you want. For light users who stay mostly in the UK, Lebara’s promotional rolling deal offers the lowest upfront cost. For unlimited data with roaming included, O2’s Unlimited Classic plan provides a balanced package. Frequent travellers should prioritise networks such as O2, Tesco Mobile, or Vodafone that include EU roaming as standard. Always check the post-promotional price and fair-use policies before committing. If you are also looking at phones, compare the best mobile phone deals with handset to see the full picture.
Frequently asked questions
What is a SIM only deal?
A SIM only deal provides a SIM card with a set allowance of minutes, texts, and data for a monthly fee, without including a phone.
Can I keep my current number with a SIM only deal?
Yes, you can port your existing number to a new SIM only provider by requesting a PAC code from your current network. The transfer typically completes within 24 hours.
Are SIM only deals cheaper than phone contracts?
Yes, SIM only deals are typically 50–70% cheaper because you only pay for the service, not the handset. Over 24 months, savings can reach several hundred pounds.
Which SIM only deal is best for light users?
For less than 5GB of data per month, Lebara, iD Mobile, and Spusu offer plans under £5/month after promotional periods. Lebara’s 5GB rolling deal at £4.95/month is a strong option.
Do SIM only deals include 5G?
Most new SIM only deals include 5G at no extra cost, but it is worth checking the plan details. Some budget plans may be limited to 4G.
What happens when my SIM only contract ends?
If you are on a 12-month or 24-month contract, the plan usually rolls over to a monthly basis at the standard rate. You can switch or cancel without penalty after the minimum term ends.
Can I switch SIM only deals before my contract ends?
Switching before the end of a minimum term may incur early termination fees. Thirty-day rolling plans offer more flexibility and can be cancelled at any time with 30 days’ notice.
What is the difference between a 30-day and a 24-month SIM only plan?
A 30-day plan offers flexibility with no long-term commitment, while a 24-month plan locks in a lower monthly rate but ties you in for two years. The best choice depends on your budget and whether you anticipate changing needs.
Do all SIM only deals include roaming?
No, roaming policies vary significantly. Some networks include EU roaming as standard, while others charge daily or weekly fees. Always check the roaming terms before signing up, especially if you travel frequently.
How often do SIM only deals change?
SIM only deals change frequently, often monthly or quarterly. Comparison sites such as Uswitch and MoneySavingExpert update their tables regularly to reflect current offers. It is worth checking a month before your current contract ends to capture the best deals.
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Sophie Marlowe is Culture & Lifestyle Editor at BritainNow.uk, covering arts, culture, lifestyle and society.