📶 Best SIM Only Deals in the UK (2025 Edition)
SIM only deals are one of the smartest ways to save on your mobile costs in 2025. Whether you’re happy with your current phone or just want to avoid long contracts, SIM only plans offer flexibility, value, and no strings attached.
In this guide, we’ll uncover the best SIM only deals in the UK, how to compare them effectively, and how UK banking tools can help you manage and save on mobile bills.
🔍 What Is a SIM Only Deal?
A SIM only deal provides you with:
-
A SIM card (with minutes, texts, and data)
-
No handset
-
Usually 1-month, 12-month, or 24-month contracts
They’re ideal for:
-
People who already own a smartphone
-
Those who want to avoid high monthly repayments
-
Users looking for better value and more control
📊 Why SIM Only Deals Are So Popular in the UK
SIM only deals are often half the price of equivalent phone contracts. They offer:
-
Greater flexibility (especially 1-month rolling deals)
-
Cheaper bills
-
Easier upgrades
-
No credit check required with many providers
If you’re switching from a pay-monthly phone contract, you could save £200–£400/year by going SIM-only.
💷 Best SIM Only Deals in the UK (June 2025)
Here’s a breakdown of some of the best value-for-money SIM only plans available right now:
| Provider | Monthly Cost | Data | Calls & Texts | Contract |
|---|---|---|---|---|
| Smarty | £8 | Unlimited | Unlimited | 1 month |
| VOXI | £10 | 30GB + Endless Socials | Unlimited | 1 month |
| iD Mobile | £6 | 10GB | Unlimited | 1 month |
| Giffgaff | £10 | 25GB | Unlimited | No contract |
| Lebara | £5 | 5GB | Unlimited | 1 month |
| EE | £15 | 30GB | Unlimited | 24 months |
| O2 | £12 | 20GB | Unlimited | 12 months |
🧠 How to Choose the Right SIM Only Deal for You
Consider these factors:
-
How much data you actually use
-
Network coverage in your area (check below)
-
Whether you prefer a contract or flexibility
-
If international calls or roaming are important
For example, Lebara Mobile offers free EU & India minutes, making it ideal for international users.
📡 Coverage: What Network Does Each SIM Use?
Some providers are powered by larger networks:
| SIM Brand | Network Used |
|---|---|
| Giffgaff | O2 |
| Smarty | Three |
| VOXI | Vodafone |
| iD Mobile | Three |
| Tesco Mobile | O2 |
| Asda Mobile | Vodafone |
| Lebara | Vodafone |
🔍 Check your signal strength with the Ofcom Mobile Checker.
🏦 How UK Banks Help You Track and Control SIM Spending
Most modern UK banks now help you track subscription payments, including mobile bills.
| Bank | Smart Feature |
|---|---|
| Monzo | Tags monthly SIM payments; sets category budgets |
| Starling Bank | Shows historical spend and alerts on price hikes |
| Barclays | Notifies you of duplicated subscriptions |
| HSBC UK | Offers mobile payment tracking through Money Manager |
These tools help ensure you’re getting value for money on your SIM-only plan.
✂️ Should You Keep or Ditch Your Current Provider?
If you’ve been with your provider for over 12 months, you might be overpaying.
Check your last 3 bills in your bank app and compare to current market rates. Then:
-
Text PAC to 65075 to get your Porting Authorisation Code (free)
-
Sign up for a new deal online
-
Give your new provider the PAC code to keep your number
You’ll switch networks within 1 working day.
🧾 Example: How Much You Can Save With SIM Only
| Usage Type | Previous Monthly (with phone) | SIM Only + Owned Phone | 12-Month Saving |
|---|---|---|---|
| Average User | £35 | £10 | £300 |
| Light User | £25 | £6 | £228 |
| Unlimited Data User | £45 | £15 | £360 |
Even if you buy a phone outright and pair it with a cheap SIM, you’ll likely save over the life of a typical 2-year contract.
🧩 Extras to Look For in SIM Only Deals
Some SIM providers offer bonuses or perks worth noting:
-
VOXI: Endless social media usage doesn’t count against data
-
Three: Go Roam (free international roaming)
-
Giffgaff: Flexible goodybags and community support
-
Tesco Mobile: Clubcard points on bills
💳 No Credit Check SIM Only Deals
If you have a poor or limited credit history, these networks don’t run credit checks:
-
Smarty
-
Giffgaff
-
VOXI
-
Lebara
-
iD Mobile (on some plans)
Perfect for students, freelancers, or those rebuilding credit.
💡 Bonus Tip: Set a Mobile Budget
To avoid unexpected bills:
-
Set a data cap through your provider
-
Use your bank’s spending alerts
-
Avoid international roaming unless included
Many banking apps (e.g. Monzo and Starling) will auto-categorise mobile spend and warn you if it increases unexpectedly.
📞 Switching Is Easier Than Ever in the UK
The PAC process now takes 60 seconds via SMS.
To switch and keep your number:
-
Text PAC to 65075
-
Sign up for a new SIM deal
-
Give the code to the new provider
No need to call your old provider or wait days.
✅ Best SIM Only Deal Summary Table
| Best Overall | Best for Data | Best No Credit Check | Best Value |
|---|---|---|---|
| VOXI 30GB £10 | Smarty Unlimited £8 | Lebara £5 5GB | iD Mobile 10GB £6 |
💬 Final Thoughts: Why SIM Only Is the Smart Choice
SIM only deals are the perfect choice in 2025 for people who want:
-
Budget-friendly contracts
-
Freedom to switch anytime
-
No commitment or hidden costs
With providers competing for your business, now’s the time to take control of your mobile spending — and UK banks make tracking it easier than ever.