SIM only deals with no price rises UK October 2026: plans where the price stays put

Last updated: Thursday 8 October 2026 (Europe/London).
Next update: when Smarty or Mozillion change these prices or their price-rise terms.
By: Switch Editorial Team, Switch Squid Ltd

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As of 8 October 2026, the simplest SIM only deal with no price rises is Smarty’s 16GB plan at £8 a month: it is a one-month rolling plan, and Smarty says it has no annual price rises and no credit check. If you would rather lock in a price for two years, Mozillion sells 150GB a month for £180 paid upfront for 24 months, equivalent to £7.50 a month, and says there are no mid-contract price rises. SwitchSquid compares both routes below, with the total you pay over a year and over two years; we may earn a commission if you buy through our links.

Sources: Smarty — 16GB plan, Mozillion — 150GB for 24 months, Mozillion — 150GB for 12 months, Ofcom — telecoms price rises and your rights and Ofcom — rules from 17 January 2025.

What Ofcom’s rules changed in January 2025

For years, many mobile contracts included a price rise every March or April linked to inflation, often with an extra 3.9% on top. Ofcom estimated that, as of April 2024, around six in ten mobile and broadband customers were on contracts with inflation-linked rises. That made it hard to know what a two-year contract would really cost.

From 17 January 2025, providers can no longer put inflation-linked or percentage-based price rises into new contracts. Any rise written into a new contract must be shown in pounds and pence, prominently, before you sign, along with the date it takes effect. Contracts signed before 17 January 2025 may still include inflation-linked terms.

The rules do not ban price rises altogether. A provider can still build a fixed rise, such as an extra £2 a month each April, into a new contract, as long as it tells you upfront. If a contract allows unspecified rises instead, Ofcom says the provider must give 30 days’ notice and let you leave without a penalty. So “no price rises” is a real feature worth looking for, not just a marketing line.

Three ways a SIM deal keeps its price steady

1. One-month rolling plans. Smarty’s plans run month to month. Smarty says its customers are never forced to accept a price increase part way through a contract, because there is no long contract to be part way through. You can cancel or change plan at any time.

2. Paying the whole term upfront. Mozillion’s 12-month and 24-month plans are paid in one go. Once you have paid £180 for 24 months, there is nothing left to increase, and Mozillion also lists no mid-contract price rises on the plan page.

3. Fixed-price monthly contracts. Some providers sell 12-month or 24-month contracts where the monthly price is fixed for the whole term. These can be good value, but check the contract summary, because the larger networks often write a set pounds-and-pence rise into each April instead.

Each route suits a different person. Rolling plans give you freedom to leave; upfront plans give you the lowest monthly equivalent if you have the cash; fixed monthly contracts spread the cost but tie you in.

SIM only deals with no price rises compared (checked 8 October 2026)

Plan	Data each month	Price	Term	Cost over 12 months	Cost over 24 months	Price-rise position
Smarty 16GB	16GB	£8 a month	1 month rolling	£96	£192	Smarty says no annual price rises; cancel any time
Smarty 5GB	5GB	£6 a month	1 month rolling	£72	£144	Smarty says no annual price rises; cancel any time
Mozillion 150GB, 12 months	150GB	£108 upfront	12 months	£108	£216 if you buy twice	Paid upfront; Mozillion lists no mid-contract price rises
Mozillion 150GB, 24 months	150GB	£180 upfront	24 months	Not sold as 12 months	£180	Paid upfront; Mozillion lists no mid-contract price rises

Totals are our own arithmetic from the prices shown on each plan page when we checked on 8 October 2026. All four include unlimited UK calls and texts. Rolling plan totals assume the price stays the same, which Smarty says it will not raise mid-plan, though a one-month plan price can change for future months with notice.

Rolling or locked in: which suits you?

Choose a rolling plan like Smarty 16GB if you want to keep your options open. You might be waiting for a new phone, planning to travel, or simply prefer not to commit. At £8 a month you pay £96 over a year, and if a better deal appears you can move with a month’s notice.

Choose an upfront plan like Mozillion 150GB if you use a lot of data and can pay in one go. Over 24 months, £180 is the lowest total in the table and gives you more than nine times the data of the Smarty 16GB plan. The trade-off is that the money is committed, so make sure the coverage works at home and at work before you buy.

If you use under 5GB a month, Smarty’s 5GB plan at £6 a month is cheaper still, at £72 over a year. Our Smarty guide covers the full range, and our Mozillion 150GB guide compares the rolling and upfront versions of that plan.

How to check a contract for price rises before you sign

1. Read the contract summary. Every provider must give you one before you sign. Look for a section on price changes and any date in March or April.
2. Look for pounds and pence. Under Ofcom’s rules, any rise built into a new contract must be shown as a cash amount, such as £1.50 or £2 a month, and when it applies.
3. Check what happens at the end. Some deals move to a higher price once the minimum term ends. Note the date so you can switch or re-contract in time.
4. Work out the full-term cost. Add every monthly payment, any upfront cost and any planned rise. A deal that looks £1 cheaper today can cost more over 24 months.
5. Keep a copy. Save the summary and order confirmation in case you need to complain later.

Switching without losing your number

You can keep your number when you move to Smarty or Mozillion. Text PAC to 65075 from your current phone to get a free Porting Authorisation Code, or text STAC to 75075 if you would rather have a new number. Smarty says a PAC or STAC stays valid for 30 days, and you can enter it while ordering or later in your account.

If you are still in a contract with another network, check for early exit charges first. Our text-to-switch guide explains the codes, and our rolling vs 18-month guide compares longer contracts with month-to-month plans.

Fit summary

• Good for Smarty 16GB at £8: light to moderate users who want a steady price, no credit check and the freedom to leave any month.
• Good for Mozillion 150GB at £180 for 24 months: heavy data users who can pay upfront and want a price that cannot change during the term.
• Consider Smarty 5GB at £6: if you mostly use wifi and need only a little mobile data.
• Consider a fixed-price monthly contract: if you want a long term but prefer to spread the cost, as long as the contract summary shows no rise.

Important conditions

• Prices and terms are as shown on each provider’s page when we checked on 8 October 2026 and can change for new customers.
• Smarty 16GB is a one-month plan; the plan page lists EU roaming with a 12GB fair use limit.
• Mozillion plans are paid upfront for the full term; check coverage before you buy.
• Ofcom’s pounds-and-pence rule applies to contracts signed from 17 January 2025.
• Confirm the price and data allowance in your basket before you pay.

Final decision card

Want flexibility and a steady price? Smarty 16GB at £8 a month, no annual price rises, cancel any time.
Want the lowest two-year total for big data? Mozillion 150GB at £180 for 24 months, paid upfront.
Signing a monthly contract instead? Read the contract summary for any pounds-and-pence rise before you agree.

FAQ

Which SIM only deals have no price rises?

Smarty says its one-month plans have no annual price rises, and Mozillion lists no mid-contract price rises on its upfront 12-month and 24-month plans. Several other smaller networks make similar promises. Always check the contract summary, because terms can differ between plans from the same provider.

Are mid-contract price rises banned in the UK?

Not completely. Since 17 January 2025, Ofcom has banned inflation-linked and percentage-based rises in new contracts, but providers can still include a fixed rise if it is shown in pounds and pence before you sign. If a contract allows other rises, the provider must give 30 days’ notice and let you leave without a penalty.

Is a rolling SIM safe from price rises?

A rolling plan cannot lock you into a higher price, because you can leave with a month’s notice. Smarty also says it does not apply annual price rises to its plans. The price for future months can still change, so check any notice you receive.

Is it worth paying for a SIM plan upfront?

It can be, if you have the cash and know the network works where you live. Mozillion’s 150GB plan at £180 for 24 months works out at £7.50 a month and the price cannot rise once paid. The downside is that the money is committed for the full term.

How much does Smarty 16GB cost over a year?

At £8 a month, Smarty 16GB costs £96 over 12 months if the price stays the same. It includes unlimited UK calls and texts and 5G where available. There is no credit check and you can cancel at any time.

Can I keep my number if I switch to a no-price-rise SIM?

Yes. Text PAC to 65075 from your current phone to get a free code, then give it to your new provider when you order or soon after. Smarty says the code stays valid for 30 days.