An MVNO (Mobile Virtual Network Operator) is a mobile provider that does not own its own network infrastructure. Instead, it uses the signal from one of the four main UK networks (O2, Vodafone, Three, or EE) and sells its own plans at lower prices. You get the same underlying coverage at a cheaper monthly cost. Examples include Giffgaff, iD Mobile, Smarty, and Lebara.

Cheap SIM Only Deals UK

Q: Is a SIM only deal better than a phone contract?

If you already own a phone you are happy with, a SIM only deal is almost always cheaper. You are not paying off a handset, so the monthly cost is lower. The only time a phone contract may work out cheaper is when a network runs a subsidised promotion on a specific handset. Always check the total cost over the contract length before deciding.

Q: Can I get a SIM only deal with no credit check?

Yes. Many 30-day rolling SIM deals and MVNO plans do not require a credit check. Giffgaff, Smarty, Lebara, and 1pMobile are examples of providers that offer plans without a formal credit check. Check the provider's terms before signing up if this is important to you.

Q: Can I switch SIM deals without changing my number?

Yes. Text PAC to 65075 (free) to get your number transfer code. Provide this to your new provider when signing up. Your number moves across within one working day, usually with only a few minutes of downtime.

Q: What happens to unused data on a SIM only deal?

It depends on the provider. Some networks reset your data allowance at the end of each month, meaning unused data is lost. Others, including Smarty and iD Mobile, offer data rollover, carrying unused data into the next month. Check the plan's terms when comparing if data rollover matters to you.

Q: Can I get a cheap SIM only deal with 5G?

Yes. 5G is now available on SIM only deals at no extra cost from most UK networks and MVNOs. You need a 5G-capable handset to use it. If your phone supports 5G, filter for 5G plans when comparing on Switch: many are available for under £15/month.

Q: What is a PAC code and how do I get one?

A PAC (Porting Authorisation Code) is the code you need to move your existing mobile number to a new network. Text PAC to 65075 (free). You receive the code by text within one working day. Provide it to your new provider at the point of sign-up to transfer your number automatically.

Q: How long does it take to switch SIM?

The comparison and sign-up process on Switch takes a few minutes. If you are porting your number using a PAC code, the number transfer typically completes within one working day, with only a brief interruption. If you are taking a new number (no PAC), your new SIM activates as soon as it arrives, or instantly if you choose an eSIM.

Q: Are there any SIM only deals without annual price rises?

Yes. Several providers, including iD Mobile, Smarty, and Lebara, commit to no annual mid-contract price rises on SIM only deals. When comparing, look for this commitment in the plan terms. Switch flags deals with and without mid-contract price rises so you can compare the true cost.

Compare cheap SIM only deals: calls, texts, and data only, no handset cost, no 24-month lock-in.

Cheap SIM Only Deals UK

Compare cheap SIM only deals: calls, texts, and data only, no handset cost, no 24-month lock-in.

What Is a SIM Only Deal?

A SIM only deal gives you a monthly allowance of minutes, texts, and mobile data on a SIM card, without a phone bundled in. The network is not subsidising any handset, so the monthly price is much lower than a standard phone contract.

SIM only suits you if you already own a smartphone, if you have bought a phone outright, or if your current handset contract has ended and you want to stop paying the device repayment element you no longer owe.

SIM Only vs Phone Contract: Quick Comparison

Switching from a 24-month handset contract to a SIM only deal when your phone is paid off could save you over £300 per year for the same data allowance.

Factor	SIM Only	Phone Contract
Monthly cost	£5 to £25/month typical	£25 to £70/month typical
Handset included	No, use your existing phone	Yes, bundled in
Contract length	30-day rolling or 12 months	24 months typical
Flexibility	High, cancel or switch easily	Low, exit fees apply
Credit check	Often not required (rolling plans)	Usually required
Potential annual saving	Up to £300+ vs phone contract	N/A

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How Much Can I Save With a Cheap SIM Only Deal?

When a 24-month phone contract ends, many people keep paying the same monthly amount, which still includes a device repayment for a phone already fully paid off. Switching removes that element immediately.

Data Needed	Typical Phone Contract	Cheap SIM Only	Monthly Saving
5GB to 15GB (light user)	£28 to £35/month	£5 to £8/month	£20 to £27/month
20GB to 50GB (average user)	£35 to £50/month	£8 to £15/month	£20 to £35/month
Unlimited data (heavy user)	£45 to £70/month	£12 to £25/month	£20 to £45/month

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Figures are indicative ranges based on May 2026 market pricing. Actual deals vary by network and promotional period.

Types of Cheap SIM Only Deals

30-Day Rolling SIM Deals: A 30-day rolling SIM deal renews every month. You can cancel at any point, usually with 30 days notice. This is the most flexible option, ideal if you think your data needs might change, if you are between contracts, or if you simply do not want to commit long-term. The monthly price is usually slightly higher than a 12-month deal for the same data.

12-Month SIM Deals: A 12-month SIM deal locks you in for a year in exchange for a lower monthly price. For most people this is the right balance, you get the savings of a fixed term without the 24-month commitment of a phone contract. At the end of the 12 months, you are free to compare again and switch to an even cheaper deal.

No-Contract SIM Deals: Some providers, mostly MVNOs, offer truly contract-free SIM deals where you pay upfront each month and can stop at any time. These are great for people who want maximum freedom or who have a limited or no credit history, as many do not require a credit check.

Unlimited Data SIM Deals: Unlimited data SIM deals are now available from every major UK network and from many budget MVNOs. Prices have dropped significantly, you can find unlimited data SIM only plans for as little as £12 to £20 per month in 2026. If you stream video, work remotely, or use mobile data as a home broadband backup, unlimited SIM deals are worth comparing.

Which Networks Offer Cheap SIM Only Deals in the UK?

There are four main UK mobile networks, O2, Vodafone, Three, and EE, plus a range of budget MVNOs (Mobile Virtual Network Operators) that use those same masts at lower prices.

O2: Wide 4G coverage and strong 5G rollout. Plans often include O2 Priority perks. 30-day and 12-month options available.
Vodafone: Good UK and international coverage. Entertainment add-ons (Spotify, YouTube Premium) available on some plans.
Three: Consistently strong 5G speeds. No annual price rises on SIM only plans. Roaming included in many deals.
EE: Widest UK mobile coverage overall. Some plans come with extras such as Apple TV+ or Amazon Prime.

When comparing cheap SIM only deals UK buyers often find the best value comes from MVNOs rather than the major networks directly, same underlying coverage, lower monthly cost.

Budget MVNOs: Often the Cheapest SIM Only Option

MVNOs use one of the four main networks infrastructure and sell plans at lower prices due to lower overheads. Coverage is identical to the parent network.

MVNO	Network Used	Plans From	Key Perk
Giffgaff	O2	£5/mo	Flexible goodybag plans. No credit check.
Smarty	Three	£5/mo	No annual price rises. Data rollover on unused data.
iD Mobile	Three	£5/mo	No annual price rises. Data rollover. 30-day cancellation on all plans.
Lebara	Vodafone	£5/mo	Competitive international calling. Plans from around £5/month.
VOXI	Vodafone	£10/mo	Social media and streaming does not count toward your data on some plans.
Tesco Mobile	O2	£7/mo	Clubcard rewards. Good choice for Tesco shoppers.

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How to Find the Cheapest SIM Only Deal: Step by Step

Five steps from checking your usage to your new SIM being active.

Check Your Actual Data Usage

Before comparing, find out how much data you actually use each month. On iPhone go to Settings then Mobile Data. On Android go to Settings then Network then Data Usage. Look at your last three months and pick the highest figure. Round up slightly so you do not run over your allowance every month.

Decide on Contract Length

30-day rolling gives you flexibility to switch whenever a better deal appears. 12-month gives you a lower monthly price. If you are fairly settled in your usage and network preference, 12-month typically gives you the best value on cheap SIM only deals in the UK.

Check Coverage in Your Area

A cheap SIM only deal on a network with poor signal where you live is not a deal at all. Use Ofcom's online coverage checker or the network's own coverage map before signing up. If only one network covers your area well, focus your comparison on that network's direct plans and any MVNOs that run on the same infrastructure.

Compare on Switch

Enter your data requirement and preferred contract length on Switch. Results show every available plan sorted by price, not by commission. You can filter by network, data allowance, contract length, 5G availability, and roaming. Every deal shows the full monthly cost with no hidden extras.

Get Your PAC Code Before You Switch

If you want to keep your existing mobile number, text PAC to 65075 (free). You will receive your PAC code within one working day by text. Give this code to your new provider when signing up. Your number will transfer automatically within one working day, with only a few minutes of downtime.

What to Watch Out for When Comparing Cheap SIM Deals

Four hidden costs and conditions that can turn a cheap deal into an expensive one.

Annual Price Rises

Some networks increase prices mid-contract each April, linked to inflation (CPI or RPI plus a fixed percentage). This can add several pounds per month to a deal you thought was fixed. Check whether a plan has annual price rises before signing up. Several MVNOs, including iD Mobile and Smarty, commit to no mid-contract price rises on SIM only deals.

Speed Caps

A small number of very cheap SIM plans apply a speed cap, limiting your download speeds to a slower rate even when you have data remaining. This may be fine for social media browsing but can cause problems if you stream video or use mobile data for work. Check the small print.

Introductory Pricing

Some plans offer a very low price for the first three to six months, then jump to a higher rate. The total cost over 12 months is what matters, not the headline monthly figure. When comparing deals on Switch, we show the full 12-month cost so you can compare like for like.

Data Rollover

Some networks and MVNOs let you roll unused data into the following month. If you are a variable user, heavy one month and light the next, data rollover means you are less likely to pay for data you never use. Look for this feature when comparing similar-priced plans.

eSIM vs Physical SIM: What You Need to Know

Most modern smartphones (iPhone XS onwards, recent Android flagships) support eSIM, a digital SIM built into the phone. With an eSIM you do not need to wait for a physical card to arrive. Your new plan activates via a QR code sent by email, usually within minutes of signing up.

If you prefer, you can still choose a physical nano SIM card. Most networks send these free by Royal Mail within two to three working days. Some networks send a three-in-one SIM card (standard, micro, and nano in one card) so you can pop out the correct size.

If you have an older phone that only takes a physical SIM, do not worry, every network still supports physical SIM cards. The comparison and switching process is exactly the same.

EU and International Roaming on Cheap SIM Deals

If you travel, roaming capability matters. Not all cheap SIM only deals include EU roaming, and on those that do, the terms vary.

Three: includes roaming in many European and international destinations on most plans at no extra cost.
O2: includes EU roaming on most pay-monthly plans.
Vodafone and EE: offer EU roaming on selected plans, with add-on packs available for others.
iD Mobile: includes roaming in 50+ destinations.
Tesco Mobile: has committed to no EU roaming charges on their plans.

If you travel frequently, filter specifically for plans with inclusive roaming when comparing on Switch. Do not assume roaming is included just because a plan is from a major network.

Can I Keep My Number When I Switch SIM?

Yes. Keeping your mobile number when switching to a new SIM only deal is straightforward and free. Here is how it works:

Text PAC to 65075 (free). You receive your PAC code within one working day.
Sign up to your chosen SIM only deal on Switch and provide your PAC code during the process.
Your number transfers automatically, typically within one working day.
There is usually only a few minutes of downtime during the actual transfer.
Your old contract is cancelled automatically once the PAC code is used. You do not need to contact your old network separately.

If you do not want to keep your number, simply sign up to a new deal without providing a PAC code. You will be given a new number with your new SIM.

Compare Cheap SIM Only Deals UK: Takes 2 Minutes

If you have not compared your mobile plan in the last 12 months, you are almost certainly overpaying. The cheap SIM only deals UK market has never been more competitive, prices have dropped and data allowances have grown. There is no paperwork, no engineer visit, and switching takes a few minutes online.

Switch compares every available SIM only deal by total monthly cost, no ranked-by-commission results, no cached pricing. Compare today, find your cheapest plan, and switch in minutes.

Compare SIM Only Deals Compare Mobile Phones Compare Broadband Expert Help: 01926 942125

FAQs

What is the cheapest SIM only deal in the UK right now?

The cheapest SIM only deals in the UK start from around £1 to £5 per month for low data allowances (1GB to 5GB), typically from MVNOs such as Lebara, Giffgaff, or Smarty. Prices change frequently, so compare live on Switch to see the cheapest available deal for your data amount today.

Is a SIM only deal better than a phone contract?

Can I get a SIM only deal with no credit check?

What is an MVNO?

Can I switch SIM deals without changing my number?

What happens to unused data on a SIM only deal?

Can I get a cheap SIM only deal with 5G?

What is a PAC code and how do I get one?

How long does it take to switch SIM?

Are there any SIM only deals without annual price rises?

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