Mobiles.co.uk is promoting two Vodafone SIM-only deals this October: 120GB for new customers at an effective cost of £5.25 a month, and 200GB for existing Vodafone customers upgrading at an effective cost of £5 a month. The word "effective" matters, so this guide from SwitchSquid explains what it means, who each deal is for and what to check on the retailer's page before you order.
Vodafone SIM deals at Mobiles.co.uk in brief
Deal | Who it is for | Data | Effective monthly cost |
|---|---|---|---|
Vodafone SIM Only 120GB | New customers | 120GB | £5.25 |
Vodafone Upgrade SIM Only 200GB | Existing Vodafone customers upgrading | 200GB | £5.00 |
The effective monthly cost is the figure Mobiles.co.uk gives once its offer is taken into account. It is not necessarily the headline price you pay each month on your bill. That is why we have written "effective cost" throughout and not "£5.25 a month" on its own. Before you order, check the retailer's page for the headline monthly price, the contract length and how the saving is delivered, whether as cashback or another reward.
SwitchSquid may earn a commission if you buy through the links on this page, at no extra cost to you. It never changes which deals we feature or how we rank them.
The new-customer deal is the main one for most readers. It gives you a very large 120GB allowance on the Vodafone network. If you are a new customer, or you are leaving another network, this is the deal to look at first.
What does "effective monthly cost" mean?
Retailers often advertise a lower number than the monthly bill by counting a reward or cashback against the total cost. Suppose a plan has a headline price of £10 a month for 24 months and the retailer gives you £110 back. The total you pay is £240 minus £110, which is £130, and that works out at about £5.42 a month. That is the "effective" cost, even though your bill still says £10.
That is only an example to show the idea, not the numbers for these deals. The point is to compare like with like. Another SIM at £6 a month with nothing back costs £144 over 24 months, while a plan with a headline £10 and a good reward can cost less. Equally, a reward that arrives months later, or needs you to claim it, can leave you out of pocket if you forget. Always read how and when the reward is paid.
Vodafone SIM Only 120GB: for new customers
With 120GB you are unlikely to run out. For context, an hour of HD video usually uses 1.5 to 3GB, so 120GB would be tens of hours of streaming every month on top of normal use. It is also enough for people who use their phone as a hotspot, as long as you keep an eye on your usage.
Who it suits:
People who currently pay for a smaller plan and keep running out.
Anyone coming from another network who wants a big allowance.
Households that use mobile data for streaming, gaming and hotspotting.
Who might want to look elsewhere: if you use less than 10GB a month, a smaller, cheaper plan could cost less overall. And if you want a flexible one-month rolling contract, check the term on this deal, because retailer SIM deals like this are usually fixed-term.
Vodafone Upgrade SIM Only 200GB: for existing customers
The second deal is specifically for people who are already with Vodafone and want to upgrade or renew their SIM-only plan. It offers 200GB at an effective cost of £5 a month. This deal is not for new customers, so if you are joining Vodafone from another network, use the 120GB deal instead.
If you are an existing Vodafone customer, the upgrade route is worth looking at when your current plan is ending. Getting a new SIM-only plan from a retailer such as Mobiles.co.uk can be cheaper than staying on the plan your provider rolls you on to, but check carefully that your current contract is over so you do not pay for two plans at once.
New customer or upgrade: which deal applies to you?
Your situation | Which deal to look at | Why |
|---|---|---|
Moving from another network | 120GB new-customer deal | You are a new customer to Vodafone |
With Vodafone and your contract is ending | 200GB upgrade deal | The upgrade deal is for existing customers |
With Vodafone and mid-contract | Check your end date first | Leaving early could mean paying the remaining months |
Not sure how much data you use | 120GB new-customer deal, if eligible | Check your usage in your current provider's app |
Things to check before you order
Headline price and contract length: confirm both on the Mobiles.co.uk page. The effective cost is a guide, and the page is the source of truth.
How the reward is paid: find out whether it is cashback, a prepaid card or another form, and when it arrives.
Eligibility: the 200GB deal is for existing Vodafone customers only, and the 120GB deal is for new customers.
Coverage: check Vodafone's coverage map for your home, workplace and regular journeys.
Unlocked phone: your handset needs to be unlocked to work with a different network's SIM.
Roaming: check Vodafone's rules if you travel outside the UK, because allowances and charges vary by destination.
How a Vodafone SIM compares with cheaper networks
Vodafone is one of the UK's four main mobile networks, and it tends to be chosen for coverage and reliability rather than for the lowest price. Budget networks that run on the same or other networks can undercut it, particularly on rolling plans. The reason to look at this deal is that the effective cost brings a big-network SIM close to budget territory. The reason to be careful is that the saving depends on the reward arriving.
A sensible check is to put three numbers side by side: the headline monthly price, the contract length, and the total you expect to pay after any reward. If the total is clearly lower than a budget SIM with the same data, the Vodafone deal is good value. If it is close, the flexibility of a rolling plan may win.
If you want a new phone as well
Mobiles.co.uk is also promoting a couple of handset deals this month. The Samsung Galaxy S26 FE 128GB is listed at £25.99 a month with 100GB of data and a free Galaxy Watch8, with a 256GB model offered at the 128GB price. There is also a refurbished iPhone 17 256GB in excellent condition at £29.99 a month with 400GB of data and £69 upfront. These are different from the SIM-only deals above, so compare the total cost over the contract before choosing. If you already have a phone you like, SIM-only is almost always the cheaper way to get Vodafone data.
How to switch to Vodafone and keep your number
Choose the deal that applies to you and check the headline price and term on the retailer page.
Complete the order, and choose a physical SIM or eSIM if both are offered.
To keep your number, text PAC to 65075 from your old SIM. The code lasts 30 days.
Give the PAC code to the retailer or Vodafone when asked.
When the SIM arrives, put it in and test calls, texts and data before cancelling anything else.
Our verdict
If you are new to Vodafone and want a large amount of data at a low effective cost, the 120GB deal is the one to look at. If you are already with Vodafone and your contract is ending, the 200GB upgrade deal gives you more data at a slightly lower effective cost. In both cases, check the real monthly price, the contract length and how the reward is paid. SIM-only is rarely worth rushing, but it pays to compare.
Details are correct as of 19 October 2026. Prices and eligibility can change, so please check the Mobiles.co.uk page before ordering.
Frequently asked questions
How much is Vodafone SIM Only 120GB at Mobiles.co.uk?
The retailer lists an effective monthly cost of £5.25 for new customers. Check the page for the headline monthly price, contract length and how the saving is paid.
Is the 200GB Vodafone deal open to new customers?
No. The 200GB deal at an effective £5 a month is for existing Vodafone customers upgrading. New customers should look at the 120GB deal.
What does effective monthly cost mean?
It is the monthly cost after a reward or saving is counted against the total. It can be lower than the headline price on your bill, so check how and when the reward is paid.
Can I keep my phone number?
Yes. Text PAC to 65075 from your old SIM to get a code, valid for 30 days, and give it to the retailer or Vodafone when you order.
Do I need an unlocked phone?
If you are moving from another network, your phone must be unlocked. Contact your current provider if you are unsure.
Is 120GB too much data?
It depends on your use. Many people use well under 50GB, but 120GB gives plenty of room for streaming, gaming and hotspot use. If you use less than 10GB, a smaller plan may cost less.
Should I buy a phone as well?
Only if you need one. SIM-only is usually cheaper if you have a handset you are happy with. If you do want a new phone, compare the total cost over the whole contract.
