Hand holding SIM card

Best SIM Only Deals UK

Already have a phone you love? Switch to SIM only, compare every UK network plan in one place, no hidden fees.

What Is a SIM Only Deal?

A SIM only deal gives you a monthly allowance of calls, texts and mobile data, without a phone included in the bundle. You pay for the SIM and the service, nothing else. Because networks are not subsidising the cost of a handset, monthly prices are significantly lower than phone contracts.
A SIM only deal is the right move if:
  • You are happy with your current phone and do not want to upgrade
  • You have just finished a phone contract and want to stop paying off a handset
  • You have bought a phone outright or received one as a gift
  • You want flexibility: 30-day rolling plans let you cancel any time with 30 days' notice
According to Ofcom research, buying a handset separately and pairing it with a SIM only plan is on average 23% cheaper than taking a combined handset-and-SIM contract. On a mid-range phone, that difference can be over £200 across 24 months.
Compare SIM Deals NowSee 5G Plans30-Day Rolling Deals

Why Use Switch to Compare SIM Only Deals UK?

  • We compare deals from EE, O2, Vodafone, Three, Giffgaff, Smarty, iD Mobile, VOXI, Lebara, Tesco Mobile, Sky Mobile and more
  • Results are ranked by total monthly cost, not by commission rate
  • Filter by network, data allowance, contract length, 5G, and roaming
  • Free, independent and Ofcom-accredited
  • Our team is reachable on 01926 942125 if you want a recommendation

Types of SIM Only Deals: Which One Is Right for You?

Choose the contract length that matches how you use your phone and how much flexibility you need.

1

30-Day Rolling Plans

The most flexible option. Cancel with 30 days' notice at any time. Monthly prices are slightly higher than 12-month contracts, but you are never locked in. Best for people who travel often, are mid-way through paying off a handset, or simply want freedom to switch the moment a better deal appears.

2

12-Month SIM Contracts

The most popular choice. Prices are lower than rolling plans, and deals are fixed for a year so you know exactly what you are paying. Best for people who are happy with their current network and want the lowest monthly cost without a long commitment.

3

24-Month SIM Only Deals

The cheapest per-month option, but you are tied in for two years. Some networks offer additional perks on 24-month plans, like extra data, inclusive roaming, and streaming subscriptions. Worth considering if you are very happy with your network and the saving is significant.

4

Pay As You Go (PAYG) SIM

No contract at all. Top up when you need to and pay for what you use. Best for very light users, people travelling short-term in the UK, or children's first phones. Not usually the best value for regular users who need data every month.

UK Mobile Networks: What You Need to Know

There are four main mobile networks in the UK: EE, O2, Vodafone and Three. Smaller providers (called MVNOs) run on these same masts and often charge less. Here is a quick comparison:

NetworkCoverage5GStrengthsMVNO Examples
EEWidest 4G + 5G in UKYesBest rural coverage, consistent speeds-
O299% 4G population coverageYesO2 Priority rewards, good urban 5GGiffgaff, Tesco Mobile, Sky Mobile
VodafoneStrong urban + suburbanYesEntertainment extras, EU roamingVOXI, Lebara, TalkMobile
ThreeStrong in citiesYesCheapest unlimited data, Go Roam abroadSmarty, iD Mobile

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MVNOs use the same network infrastructure as their parent provider, so coverage is identical. The difference is price: MVNOs typically charge 20 to 40% less for similar data allowances because they have lower overheads.

How Much Data Do You Actually Need?

Most people overestimate how much data they use, and pay for data they never touch. Check your actual usage before you compare: iPhone: go to Settings, then Mobile Data, then scroll down to see monthly data used. Android: go to Settings, then Network, then Data Usage.

Monthly Data UsageTypical UserRecommended Plan
Under 3GBLight user, mostly on WiFi at home and work1 to 5GB plan
3GB to 10GBModerate user, social media, some streaming on the go5 to 15GB plan
10GB to 30GBRegular user, daily streaming, video calls out of WiFi20 to 30GB plan
30GB to UnlimitedHeavy user, remote work, mobile hotspot, lots of travelUnlimited plan

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If you are frequently near the top of your allowance, go one tier up. Charges for exceeding your data allowance are expensive. Unlimited plans are often only a few pounds more than large data plans and remove the worry entirely.

How to Keep Your Number When You Switch SIM

You do not have to change your phone number when you switch networks. The process is simple and free:

1

Check You Are Out of Contract

Text INFO free to 85075 to confirm your contract status and whether any exit fees apply.

2

Request Your PAC Code

Text PAC free to 65075. You will receive your Porting Authorisation Code within 1 working day at no charge.

3

Compare and Sign Up

Use Switch to find your best SIM only deal. Select your new plan and complete the sign-up. No need to contact your current network.

4

Provide Your PAC Code and Transfer

Give your PAC code to the new network when signing up. Your number transfers automatically, usually within 1 working day. Your old contract cancels automatically. Important: do not cancel your old contract before getting your PAC code, you will lose your number permanently if you do.

eSIM: Do I Need a Physical SIM Card?

An eSIM is a digital SIM built into your phone. Instead of inserting a physical card, you download a profile from your new network. Most phones released since 2020 support eSIM, including all iPhones from the XS onwards and most Samsung Galaxy S and A series devices.
Benefits of eSIM:
  • Instant activation: no waiting for a SIM card to arrive in the post
  • Dual SIM capability on many phones: keep a personal and work number on one device
  • No risk of losing or damaging a physical SIM card
Not all UK networks support eSIM on all plans, so Switch filters results to show you which deals are available as eSIM for your device.

SIM Only Deals with Roaming: What to Know

Roaming rules vary significantly between networks since the UK left the EU. Some networks include roaming in certain plans; others charge a daily fee. If you travel regularly, check roaming terms before you sign up. Always check the current terms on the network's site as these can change.

NetworkRoaming Offer (2026)Countries Included
VodafoneSelect plans include EU roaming52 European destinations
ThreeGo Roam included on most plans71 destinations worldwide
O2Daily roaming charge applies£4.99/day in Europe
EESmart plans include EU roamingSelect European countries
Smarty (Three MVNO)EU roaming on most plansVaries by plan
Giffgaff (O2 MVNO)EU roaming included on Goody BagsEU destinations

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SIM Card Sizes: Which One Does Your Phone Take?

Most modern phones use a Nano SIM. Almost all networks send a 3-in-1 SIM (also called a multi-SIM or combi SIM) that includes all three sizes in one card, so you simply pop out the size you need. If you are not sure, check your phone's manual or the manufacturer's website.

SIM TypeSizeUsed In
Standard SIM25mm x 15mmOlder phones, rarely used today
Micro SIM15mm x 12mmMid-2010s devices
Nano SIM12.3mm x 8.8mmAll current smartphones
eSIMDigital (no physical card)Most phones from 2020 onwards

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Do SIM Only Deals Include 5G?

Yes. 5G is now standard on most SIM only plans from all four major UK networks, with no extra cost. As of 2026, Ofcom data shows that 85 to 93% of UK premises can receive outdoor 5G coverage from at least one network. Urban areas have the best coverage; rural areas are improving steadily.
To use 5G, your handset must be 5G-compatible. If your phone is 4G only, a 5G SIM will work perfectly: you will just connect at 4G speeds. You can check network 5G coverage at your home and workplace using the Ofcom coverage checker at checker.ofcom.org.uk.

How Much Can You Save With a SIM Only Deal?

The biggest saving comes when your phone contract ends and you stay on the same plan without switching to SIM only. At that point you are still paying the full monthly price, including a handset you have already paid off. Moving to a SIM only plan removes that cost immediately.

ScenarioTypical Phone Contract CostSIM Only CostEstimated Monthly Saving
Keeping your phone after contract ends£35 to £55/month (still paying for the handset)£8 to £20/month£15 to £35/month
Buying a phone outright + SIM only£45 to £60/month (contract bundle)£10 to £25/month£20 to £35/month
Switching from PAYG to SIM onlyVariable, often £20 to £40 for low data£5 to £15/month for same data£5 to £25/month

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Compare SIM Only Deals UK: Free, Fast, Independent

Switch compares hundreds of sim only deals uk from every major network and MVNO in one place. Enter your data needs, choose your contract length, and see the cheapest options available right now, ranked by total monthly cost, not commission.

The comparison is completely free. There is no obligation to switch. If you want help choosing, our team is available on 01926 942125.

Compare SIM Deals NowSee 30-Day Rolling PlansSee 5G SIM DealsCall Us: 01926 942125

FAQs

What is the difference between a SIM only deal and a phone contract?

A phone contract bundles a handset and a SIM together. You pay a monthly amount that covers both the phone cost and the airtime. A SIM only deal is just the airtime: calls, texts and data. Because there is no handset to pay off, monthly prices are much lower.

Can I keep my current phone number when I switch to a SIM only plan?
What happens to my current contract when I switch?
Are sim only deals uk available with 5G?
What is a 30-day rolling SIM deal?
What is an MVNO and should I consider one?
How do I know which network has the best coverage where I live?
Can I get a SIM only deal without a credit check?
What is an eSIM and do I need one?
How often should I compare SIM only deals?

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