If your phone contract has ended, switching to a SIM only deal can save you £200-400/year instantly. You keep your phone, keep your number (via a PAC code), and pay only for the service — not for a handset you've already paid for. In April 2026, unlimited data SIM only deals are available from just £8/month on 30-day rolling contracts, with no commitment. Here's what each major UK network and MVNO offers.
Key Facts
Cheapest unlimited data: from ~£8/month (SMARTY/iD Mobile) | Cheapest plan overall: from ~£5/month (small data) | Keep your number: text PAC to 65075 (free, instant) | Switch in: 1 working day
Best SIM Only Deals UK April 2026
Indicative prices April 2026 — SIM only deals change weekly. Always compare on Uswitch, MoneySuperMarket, or Ofcom's comparison tool for today's best deal.
Provider
Network
Plan / Data
Price/Month
Contract
5G?
SMARTY
Three
Unlimited data + calls + texts
From ~£8-10
30-day rolling
✅ Yes
iD Mobile
Three
Unlimited data
From ~£8-12
30-day or 12-month
✅ Yes
Lebara
Vodafone
Unlimited + international calls
From ~£10-14
30-day
✅ Yes
Tesco Mobile
O2
5GB-10GB plans
From ~£7.50
30-day or 12-month
✅ Yes (select plans)
Sky Mobile
O2
Data rollover — unused data saved
From ~£8-15
30-day
✅ Yes
Three (direct)
Three
Go Binge — unlimited streaming apps
From ~£10-16
30-day or 12-month
✅ Yes
O2 (direct)
O2
Priority perks, O2 deals
From ~£14-22
30-day or 12-month
✅ Yes
Vodafone (direct)
Vodafone
Entertainment extras included
From ~£14-22
30-day or 12-month
✅ Yes
EE (direct)
EE
Best network coverage UK
From ~£16-25
30-day or 12-month
✅ Yes
giffgaff
O2
Community support, flexible goody bags
From ~£6-15
Monthly (no contract)
✅ Yes (select)
30-Day Rolling vs 12-Month SIM Only — Which Is Better?
Feature
30-Day Rolling
12-Month Contract
Monthly price
Slightly higher
Usually 10-20% cheaper
Flexibility
Cancel or switch anytime
Early exit fees if you leave early
Best for
Uncertain plans, frequent switchers
Those happy with the deal who want to save
Switching networks
Can switch every month for best deal
Locked in for 12 months
Coverage risk
Can switch if coverage is poor
Stuck with poor coverage for 12 months
UK Mobile Network Coverage Map 2026
Network
4G UK Coverage
5G UK Coverage
Best Coverage Area
EE (BT)
99% of UK population
Growing rapidly
Best rural coverage in UK
O2 (Virgin Media)
99%
Good urban coverage
Strong in cities and transport links
Vodafone
99%
Good urban coverage
Strong business coverage
Three
99%
Good urban, weaker rural
Best unlimited data value
SMARTY
Runs on Three
Three 5G where available
Same as Three
giffgaff
Runs on O2
O2 5G where available
Same as O2
How to Switch SIM Only and Keep Your Number
Step 1: Text 'PAC' to 65075 — free, response within 60 seconds
Step 2: Compare deals on Uswitch or MoneySuperMarket
Step 3: Sign up with new provider, give them your PAC code
Step 4: New SIM arrives in 1-3 days; number transfers in 1 working day
Step 5: Your old contract cancels automatically once PAC is used
Note: If you just want to leave without porting, text 'STAC' to 75075 for a 30-day notice code
Frequently Asked Questions
What is the best SIM only deal UK 2026?
The best SIM only deal depends on your data needs. For unlimited data at the lowest price, SMARTY (uses Three network) and iD Mobile regularly offer unlimited plans from £8-12/month on 30-day rolling contracts. For 5G unlimited data with a trusted big name, Three and Vodafone offer competitive unlimited plans from £12-18/month. For those needing less data, Tesco Mobile and SMARTY offer 5GB-10GB plans from £5-8/month. Always check coverage in your area before switching.
What is a SIM only deal?
A SIM only deal gives you a SIM card with calls, texts and data — without a phone handset bundled in. This is the cheapest way to use a mobile phone if you already own a phone outright (or are keeping your current phone after a contract ends). SIM only plans are typically 30-day rolling (flexible, cancel anytime) or 12-month contracts (usually cheaper). They cost significantly less than handset contracts — typically £8-20/month vs £30-60/month for phone + SIM bundles.
How do I keep my number when switching SIM?
To keep your mobile number when switching, request a PAC code (Porting Authorisation Code) from your current provider. Text 'PAC' to 65075 — this is free and your provider must respond within 60 seconds with your PAC code. Give this code to your new provider when signing up. Your number will transfer within 1 working day. You can also request a 30-day notice STAC code (Service Termination Authorisation Code) if you don't want to keep your number. Never cancel before getting your PAC code or you'll lose your number.
Is 5G worth it on a SIM only plan UK?
5G is worth it if: you're in an area with good 5G coverage (check your network's coverage checker), you use your phone for heavy data tasks (streaming 4K, video calls, gaming), or the price difference vs 4G plan is small. In 2026, 5G coverage in UK cities is generally good across O2, EE, Vodafone, and Three. Rural coverage remains patchy. The speed difference for browsing and standard streaming is minimal — 5G primarily benefits users who download large files or use mobile data as their primary internet connection.
Disclaimer: Rates and prices change — always verify with the provider. Sources: Uswitch, Ofcom, SMARTY, iD Mobile, Three, O2, Vodafone, EE — April 2026. April 2026.
The content on Kaeltripton.com is for informational and educational purposes only and does not constitute financial, investment, tax, legal or regulatory advice. Kaeltripton.com is not authorised or regulated by the Financial Conduct Authority (FCA) and is not a financial adviser, mortgage broker, insurance intermediary or investment firm. Nothing on this site should be construed as a personal recommendation. Rates, figures and product details are indicative only, subject to change without notice, and should always be verified directly with the relevant provider, HMRC, the FCA register, the Bank of England, Ofgem or other appropriate authority before any financial decision is made. Past performance is not a reliable indicator of future results. If you require regulated financial advice, please consult a qualified adviser authorised by the FCA.
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Chandraketu Tripathi
Finance Editor · Kaeltripton.com
Chandraketu (CK) Tripathi, founder and lead editor of Kael Tripton. 22 years in finance and marketing across 23 markets. Writes on UK personal finance, tax, mortgages, insurance, energy, and investing. Sources: HMRC, FCA, Ofgem, BoE, ONS.
