switching from contract to sim only UK

Switching from Contract to SIM‑Only in the UK (2025 Guide)

Many UK mobile users are now moving away from long-term contracts to flexible SIM‑only plans. The reasons are clear: lower monthly bills, no handset tie-ins, and the freedom to switch networks whenever you like. If you’ve been on a 24-month contract and are tired of paying high monthly fees for a phone you already own, this guide will show you exactly how to make the switch smoothly.

Why Switch to SIM‑Only?

Lower monthly costs: Without the cost of a handset being spread across your contract, SIM‑only plans are often 50–70% cheaper.
Flexibility: Rolling monthly contracts mean you can cancel or switch anytime.
Access to better deals: Many MVNOs (like Smarty, VOXI, and Giffgaff) offer competitive rates on Three, EE, Vodafone, and O2 networks.
Control over data: You can choose the exact amount of data you need without overpaying.

Step-by-Step: Moving from Contract to SIM‑Only

Check your current contract: Identify any early termination fees (ETFs) or remaining months. Some providers may waive fees if you’ve fully paid your handset.
Decide on the SIM‑only plan: Compare UK SIM‑only options using your network’s own plans or MVNOs. Consider data allowances, network coverage, and cost. I personally use Smarty on Three’s network — rolling contracts and unused data refund is a lifesaver.
Request PAC code: To switch while keeping your number, you need a PAC (Porting Authorisation Code) from your current provider. This is usually issued within a day.
Order your new SIM‑only plan: You can do this online or in-store. Ensure it supports your current phone if you’re keeping it.
Activate your new SIM: Insert the SIM, follow carrier instructions, and use your PAC code to transfer your number. Activation typically completes within 24 hours.
Confirm cancellation of your old contract: Once your number has ported, your old contract will end automatically.

Tips & Warnings

Ensure your handset is unlocked if moving to a new network. Most modern devices sold after 2015 are already unlocked.
Double-check coverage in your area, especially if switching to a new network or MVNO.
Don’t forget to back up contacts and data before switching SIMs.
Watch out for plans that throttle speeds after certain data thresholds, even if labelled “unlimited.”

Real-World Benefits

Switching to SIM‑only saved me over £25 per month while keeping my existing phone. I also gained the flexibility to test MVNOs like VOXI and Giffgaff for better data deals, and the hassle-free month-to-month contract meant no long-term commitment. The freedom to switch networks if coverage drops is a game-changer.

Internal Topic Hub Links

Connectivity & Network hub
Battery & Power hub
Performance & System hub

Final Thoughts

Moving from a contract to SIM‑only in the UK is now faster and simpler than ever. By understanding your current contract, using a PAC code to keep your number, and choosing the right SIM‑only provider, you can enjoy lower bills, better control over your data, and the freedom to switch whenever you like. Personally, I would always recommend reviewing MVNOs — they often offer the best balance of price, data, and flexibility.