SIM-only deals for light users: PAYG or monthly?
Last checked November 2026. Offers and rules change: confirm with the provider before you rely on them.
If you already own your phone and use it lightly, a SIM-only deal is the cheapest way to run it. Light users can pay just a few pounds a month, and you can keep your existing number when you move by texting PAC to 65075.
What "SIM-only" means
A SIM is the tiny card inside a mobile phone that connects it to a network and holds your number. A SIM-only deal gives you the SIM and an allowance of calls, texts and mobile data (internet use away from Wi-Fi), but no phone. Because you are not paying off a handset, it costs far less than a phone contract.
Who these deals suit
They suit anyone whose phone contract has ended but who is still paying the same monthly price, anyone with a simple mobile used mainly for emergencies, and smartphone users who are mostly on Wi-Fi at home. If you are out of contract and happy with your phone, switching to SIM-only is one of the easiest savings there is.
The main types
| Type | How it works | Best for |
|---|---|---|
| Traditional pay as you go (PAYG) | You top up with credit and pay for each minute, text and megabyte as you use it | A phone kept for emergencies and rarely used |
| PAYG bundles | You pay a fixed sum for a 30-day pack of minutes, texts and data, with no contract | Regular light use with full control |
| 30-day rolling SIM-only | Billed monthly by direct debit; leave with a month's notice | Flexibility |
| 12-month SIM-only | Billed monthly; tied in for a year, often at a lower price | People happy to stay put |
How much do you need?
- Calls and texts. Most monthly plans now include unlimited calls and texts. On traditional PAYG, per-minute rates can be high, so a few long calls can cost more than a month's bundle.
- Data. If you use Wi-Fi at home, 1 to 5 gigabytes (GB) a month covers messages, maps, email and light browsing. Watching video away from home uses far more. Your phone's settings show how much you have used.
What to look for
- Coverage at home and where you go. The UK has a small number of main networks, and many cheaper brands, including supermarket mobile services, run on one of them. Use the mobile coverage checker on Ofcom's website for your postcode, indoors and out.
- Price rises. Since 17 January 2025, Ofcom rules require any mid-contract rise in a new contract to be stated up front in pounds and pence. Read that line before signing a 12-month deal.
- Spending caps. You have the right to ask your provider to cap your monthly bill, so going over an allowance cannot cause a shock.
- How to top up on PAYG: by card, by phone, or with a voucher from a shop.
- 4G calling and Wi-Fi calling support for your phone, which improves indoor reception.
Rough price guide
As a rough guide at the time of writing (November 2026), light-use SIM-only plans with a few gigabytes of data commonly cost from around £4 to £10 a month, and plans with generous data from around £10 to £20. Deals change weekly, so compare on the day using a price comparison site. Some networks also offer cheaper mobile "social tariffs" for people on certain benefits; ask your provider.
Keeping your number: the PAC code
You do not lose your number when you change network. Ofcom's "text-to-switch" rules make it simple:
- Choose and order your new SIM. Wait until it arrives.
- From your current phone, text the word PAC to 65075. It is free. Your current provider must reply by text, normally within a minute, with your PAC (porting authorisation code) and details of any charges for leaving early.
- Give the PAC to your new provider online, by phone or in store. The code is valid for 30 days.
- Your number moves across, normally within one working day. Put the new SIM in your phone when told to. Your old service ends automatically; you do not need to ring to cancel.
Two more free text codes are worth knowing. Text INFO to 85075 to find out whether you are still in contract and what it would cost to leave, without requesting a code. Text STAC to 75075 if you want to leave but do not want to keep your number. If you have several numbers on one account, you may need to ask for the PAC by phone or online instead. Ofcom's guide to switching mobile provider has the full process.
Setup tips a family member can help with
- Check the phone is "unlocked" so it accepts another network's SIM. Phones sold in the UK in recent years are sold unlocked; older ones may need unlocking by the original network.
- Check whether contacts are saved on the old SIM or on the phone, and copy them to the phone first.
- Swap the SIM, restart the phone and test a call, a text and mobile data.
- Set up the direct debit or automatic top-up, and add a spending cap.
- Write down the new provider's name, the account login and the customer service number.
Mistakes to avoid
- Carrying on paying a phone contract after it ends. You may be paying for a handset you already own.
- Paying for unlimited data when you use two gigabytes.
- Choosing on price without checking signal at home.
- Letting a PAYG SIM go unused. Networks can disconnect a SIM, and its credit, after a long period without use. Check your network's policy and make a chargeable call or text every so often.
- Cancelling the old service before moving the number. Use the PAC and the number moves safely.
Common questions
Is pay as you go cheaper than a monthly plan?
Only for very occasional use. If you make calls most weeks, a cheap monthly bundle usually costs less and is more predictable.
Will I have to pay to leave my current provider?
Only if you are inside a minimum term. Text INFO to 85075 to find out.
Can I move my landline number in the same way?
No, landlines use a different process; your new provider arranges it. See broadband for over-60s.