Want to cut down on mobile bills without sacrificing data or coverage? SIM only plans are the answer. In 2025, more UK consumers are ditching phone contracts in favour of affordable SIM only deals that give them the flexibility, savings, and freedom they need.
Whether you’re a student, working professional, or just smart with money, this guide is your go-to list of the top 5 affordable SIM only plans in the UK, all vetted for value, speed, and network quality. Ready to save without compromise? Let’s dive into the best options available right now.
1. Giffgaff Goodybags – Best for Flexibility
Overview:
Giffgaff offers contract-free SIM only deals with monthly plans known as “Goodybags.” You can change, pause, or cancel anytime, perfect for users who hate being locked in.
Top Plan (as of June 2025):
- £10/month
- 20GB data
- Unlimited UK calls & texts
- 5G included on O2’s network
Why it’s great:
- No contract
- Unused data rolls over
- Community-driven support
Bonus Insight:
Giffgaff is consistently rated one of the most trusted UK mobile providers, especially for younger and budget-conscious users.
2. SMARTY by Three – Best for Unlimited Data on a Budget
Overview:
SMARTY, owned by Three, offers one of the cheapest unlimited data SIM only plans in the UK. They also refund unused data for light users.
Top Plan:
- £20/month
- Unlimited data (including tethering)
- Unlimited calls & texts
- No speed caps
Budget Option:
- £8/month
- 12GB data
- Money-back for unused data
Why it’s great:
- Excellent for heavy streamers or remote workers
- No credit checks
- Powered by Three’s 5G network
Table: SMARTY Pricing Snapshot
| Plan | Price | Data | Contract |
|---|---|---|---|
| Value Plan | £8 | 12GB | No |
| Unlimited Plan | £20 | Unlimited | No |
3. VOXI by Vodafone – Best for Social Media Lovers
Overview:
VOXI caters to young, digitally-savvy users with endless social data. That means apps like Instagram, TikTok, Snapchat, and WhatsApp don’t eat into your allowance.
Top Plan:
- £12/month
- 30GB data
- Unlimited social apps
- Unlimited calls & texts
Why it’s great:
- Ideal for content creators and students
- Powered by Vodafone’s strong UK coverage
- 5G-ready on all plans
Example:
You can stream endless TikToks and scroll Instagram all day, and still have your 30GB untouched for Netflix or browsing.
4. Lebara Mobile – Best for International Calls
Overview:
Lebara runs on the Vodafone network and is a favourite among expats and international students due to generous global call allowances.
Top Plan:
- £10/month
- 15GB data
- Unlimited UK mins & texts
- 100 international mins to 41 countries
Why it’s great:
- No contract
- Excellent for calling India, Pakistan, Europe, and more
- Low-cost roaming in the EU
Table: Key International Destinations on £10 Plan
| Country | Free Minutes Included |
|---|---|
| India | 100 mins |
| Pakistan | 100 mins |
| USA | 100 mins |
5. iD Mobile – Best Data Rollover Plan
Overview:
Backed by Carphone Warehouse and powered by the Three network, iD Mobile offers a unique data rollover feature, so unused data isn’t wasted.
Top Plan:
- £6/month
- 5GB data
- Unlimited texts & minutes
- 1-month rolling contract
Why it’s great:
- UK’s most affordable plan with rollover
- Data lasts an extra month
- App lets you track usage easily
Example:
If you use only 3GB this month, you get 2GB rolled over next month, perfect for light data users who want more control.
Top SIM Only Deals (June 2025)
| Provider | Price/Month | Data | Notable Perk |
|---|---|---|---|
| Giffgaff | £10 | 20GB | No contract |
| SMARTY | £8–£20 | 12GB–Unlimited | Unused data refund |
| VOXI | £12 | 30GB | Unlimited social data |
| Lebara | £10 | 15GB | 100 international mins |
| iD Mobile | £6 | 5GB | Data rollover |
How to Choose the Right SIM Only Plan
Start by identifying your priorities:
- Heavy streaming or gaming? Go with SMARTY or VOXI.
- International calls? Lebara is your best bet.
- Lowest monthly bill? Try iD Mobile.
- Want flexibility? Giffgaff has no strings attached.
Also consider:
- Network coverage in your area (Three, Vodafone, O2, EE)
- Customer reviews and Trustpilot ratings
- Whether you need 5G access, roaming, or hotspot data
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Conclusion
Switching to a SIM only plan in the UK is one of the smartest financial decisions you can make in 2025. With options like Giffgaff, SMARTY, and Lebara, you can tailor your mobile plan to your exact needs, without overpaying or being tied down.
The top 5 affordable SIM only plans in the UK we covered offer excellent value, from flexible data to social streaming perks and international calling. Just pick the one that fits your lifestyle best, and start saving today.
FAQs
1. What is the cheapest SIM only plan in the UK right now?
The cheapest plan is currently iD Mobile’s £6/month plan with 5GB data, unlimited calls/texts, and data rollover.
2. Are SIM only deals better than phone contracts?
Yes — if you already own a phone. SIM only deals offer more flexibility, savings, and often better data value.
3. Can I keep my number when switching to a SIM only plan?
Absolutely. Just request a PAC code from your old provider and share it with your new one.
4. Which SIM only plan is best for international calls?
Lebara is the top choice, offering up to 100 minutes to 40+ countries even on low-cost plans.
5. Is 5G included in SIM only plans?
Yes — most providers like VOXI, SMARTY, and Giffgaff include 5G access at no extra charge.