If you’re happy with your current phone, switching to SIM-only is often the cheapest option because you avoid paying for a new handset. If you need a replacement, buying outright with a separate SIM can offer good value, but a discounted phone contract could cost less overall.
The right choice depends on the handset you want, what you can comfortably pay upfront and the full cost of the deal. This guide explains the differences and shows you how to compare them fairly.
SIM-only, phone contract and SIM-free: what’s the difference?
| Option | What’s included? | Main consideration |
|---|---|---|
| Phone contract | A handset and a mobile plan with data, minutes and texts | Spreads the cost, but commits you to ongoing payments |
| SIM-only | A mobile plan without a handset | Useful if you already have a suitable phone |
| SIM-free phone bought outright | A handset purchased separately from your mobile plan | Higher upfront cost, with freedom to choose your SIM separately |
SIM-only and SIM-free mean different things. SIM-only is the mobile plan; SIM-free is the phone. You can buy a SIM-free handset and use it with a SIM-only plan.
When should you choose a phone contract?
A phone contract can make sense when you need a new handset and want to spread the cost.
You’ll usually pay a monthly amount and may also have an upfront payment. Depending on the provider, the handset and mobile service may be bundled together or covered by separate agreements.
A contract can also be competitive on price. Retailer promotions and handset discounts mean buying separately isn’t automatically cheaper.
Before choosing, check:
- The upfront payment.
- Every monthly payment, including scheduled increases.
- The length of the handset and airtime agreements.
- Any compulsory fees.
- What you would owe if you wanted to leave early.
A smaller monthly payment can look attractive, but spreading repayments over longer may increase the overall cost or leave you paying for the handset for longer than you expected.
Start by comparing mobile phone deals, then check the complete payment schedule for your shortlist.
When is SIM-only better value?
SIM-only is worth considering first if your phone still works well.
Without a new handset to pay for, you can focus on finding the right allowance and network for your budget. There’s little benefit in replacing a phone you’re happy with simply because your existing agreement is ending.
SIM-only plans come with different commitments. Some renew monthly, while others have a longer minimum term. Pay-as-you-go options are also available, with their own allowance and renewal rules.
Check your recent data usage before choosing. Paying extra for a much larger allowance won’t necessarily improve your experience if you rarely use what you already have.
You can compare SIM-only deals to find a plan that suits your usage and preferred commitment.
If you’re still paying off your current handset, include those remaining payments when assessing how much switching could save.
Is buying a phone outright cheaper?
Buying outright can be cheaper than a phone contract, particularly if you find a discounted handset and pair it with a suitable SIM-only deal.
It also lets you choose the phone and mobile plan independently. You could keep your existing SIM, switch to another provider or consider a refurbished handset to reduce the purchase price.
The main drawback is the upfront payment. A lower total cost still needs to fit your immediate budget.
If you choose this route, compare the same model, storage capacity and condition against the contract offer. A refurbished phone and a brand-new phone aren’t a like-for-like comparison.
Browse SIM-free phones to see the handset options available separately from a mobile plan.
How to compare the total cost
Use the same comparison period and similar data, minutes and texts for both options.
Phone contract: upfront payment + all monthly payments + compulsory fees.
Buying outright with SIM-only: handset purchase price + all SIM payments + compulsory fees.
Include scheduled price rises, introductory discounts ending and any payments that continue beyond your comparison period.
Example: comparing costs over 24 months
| Cost | Phone contract | Buy outright + SIM-only |
|---|---|---|
| Upfront handset payment | £49 | £599 |
| Monthly payment | £35 | £10 |
| Monthly payments over 24 months | £840 | £240 |
| Total over 24 months | £889 | £839 |
These are fictional examples, assuming the same new handset, equivalent allowances, no price rises and no additional fees.
Buying outright is £50 cheaper in this example. However, it requires £550 more upfront.
Keeping your existing phone with the example £10 SIM-only plan would cost £240 over the same period, assuming there are no remaining handset payments.
Different offers can produce a different result. Always calculate the figures for the deals you’re actually considering.
Check coverage before choosing a network
Price matters, but so does being able to use your phone where you need it.
Use Ofcom’s Map Your Mobile coverage checker to compare predicted signal at home, at work and in other places you regularly visit. Look at indoor coverage as well as outdoor coverage.
The results are a guide. Buildings, terrain, network congestion and your handset can all affect your actual reception.
If your chosen provider isn’t listed, check which underlying network it uses, then review the provider’s own coverage and plan information.
Remember to include price rises
The advertised starting price may not be what you pay throughout the agreement.
For new UK consumer contracts, scheduled price rises written into the agreement must be explained upfront in pounds and pence, including when they will happen. You can read Ofcom’s guidance on contract price rises for more detail.
When comparing deals, add up each pricing period separately. Multiplying the starting monthly price by the contract length will understate the cost if increases apply.
For rolling plans, remember that today’s price may not be guaranteed for your whole comparison period.
Frequently asked questions
Does SIM-only mean no contract?
No. SIM-only means the deal doesn’t include a handset. The plan may have a rolling monthly arrangement or a longer minimum term. Check the cancellation and renewal terms before ordering.
Can I use a SIM-only plan in my current phone?
Usually, provided the phone is unlocked, compatible with the provider and supports the physical SIM or eSIM you choose. Check these details before switching.
Is a phone contract always more expensive?
No. A discounted handset bundle can cost less than buying the same phone and mobile plan separately. Compare the complete cost rather than assuming one route will always win.
Should I keep my phone after the contract ends?
If it still meets your needs, keeping it can help you avoid another handset purchase. Review your mobile plan and any remaining device payments so you know what you’re paying for.
Which option is right for you?
Keep your current phone and consider SIM-only if you’re happy with it and want to reduce spending.
If you need a replacement, compare a phone contract with buying the same handset outright and arranging your SIM separately. Check the full cost, coverage and commitment before deciding.
Explore mobile phone deals or SIM-only plans on Hey Mobile to compare your next options.