Mobile Contracts Explained

Understand What You Are Signing Up For

Mobile contracts can look simple.

You choose a phone or SIM, pick a data allowance and then pay each month.

However, there is often more to consider.

For example, you need to think about the contract length, handset cost, data allowance, price changes and what happens if you want to leave early.

In addition, some deals separate the cost of the phone from the cost of the mobile service.

So, before choosing a contract, it helps to understand exactly what you are paying for.

This guide explains the main types of mobile contract and the things to check before you agree.

What Is a Mobile Contract?

A mobile contract is an agreement between you and a mobile provider.

In return for regular payments, you receive a mobile service.

Depending on the deal, this may include:

  • Calls
  • Texts
  • Mobile data
  • A new phone
  • Roaming
  • Other services or extras

However, not every contract includes a handset.

Therefore, one of the first things to understand is whether you are paying for:

The mobile service only

or:

The mobile service and a phone

That difference can have a big effect on the price.

What Is a Pay-Monthly Contract?

A pay-monthly contract means you receive mobile service and pay a regular monthly bill.

Usually, the package includes an allowance of:

Calls

Texts

and:

Data

Many contracts now include unlimited UK calls and texts.

However, data allowances can vary greatly.

For example, one deal may include 10 GB of data, while another may offer 100 GB or unlimited data.

Therefore, compare what you actually need.

What Is a Handset Contract?

A handset contract includes a mobile phone as part of the deal.

Instead of buying the phone outright, you spread the cost through regular payments.

This makes expensive phones easier to afford upfront.

However, spreading the cost does not make the phone free.

You are still paying for it.

Therefore, always look at the total amount you will pay, rather than only the monthly figure.

Your Phone and Airtime May Be Separate

Some mobile deals split your monthly payment into two parts.

For example:

Device payment

This pays for the phone.

and:

Airtime payment

This pays for calls, texts and data.

This can make the costs easier to understand.

It may also mean that different terms apply to each part.

Therefore, check whether your deal contains one agreement or more than one.

What Is a SIM-Only Contract?

A SIM-only contract gives you the mobile service without a new phone.

You simply use the SIM or eSIM with a handset you already own.

As a result, SIM-only deals can be much cheaper.

For example, if your current phone still works well, you may not need to replace it.

Instead, you could keep the phone and move to a cheaper SIM-only plan.

This can be one of the simplest ways to reduce your mobile costs.

What Is a Rolling SIM Contract?

Some SIM-only deals run from month to month.

These are often called:

Rolling contracts

or:

30-day contracts

They can offer more flexibility than a long contract.

For example, you may be able to leave with relatively short notice.

However, always check the actual terms.

A rolling contract does not necessarily mean you can cancel instantly.

What Is Pay As You Go?

Pay As You Go works differently from a normal monthly contract.

Instead of committing to a long agreement, you pay for the mobile service as you use it or buy a bundle in advance.

This can work well for some people.

For example, it may suit someone who uses their phone very little.

It can also make spending easier to control.

However, frequent users may find that a monthly plan offers better value.

So, compare based on your actual use.

How Long Are Mobile Contracts?

Contract lengths vary.

For example, you may see:

1 month

12 months

24 months

or longer.

Handset payment plans can sometimes run for several years.

A longer term can make the monthly payment look lower because the handset cost is spread over more months.

However, you will also be committed for longer.

Therefore, don’t choose a contract based on the monthly payment alone.

Check how long you will be paying it.

A Lower Monthly Price Can Be Misleading

Imagine two phone deals.

Deal A

£40 per month for 24 months

The total is:

£40 × 24 = £960

Deal B

£30 per month for 36 months

The total is:

£30 × 36 = £1,080

Deal B looks cheaper each month.

However, you pay for an extra year.

As a result, it costs £120 more overall.

So, always calculate the total.

Check for an Upfront Cost

Some handset contracts require an upfront payment.

For example:

£99 upfront

plus:

£35 per month

Therefore, you need to include both figures when comparing deals.

Suppose the contract lasts 24 months.

First:

£35 × 24 = £840

Then add:

£99

So, the total is:

£939

This gives you a much clearer picture of the real cost.

What Is a Data Allowance?

Your data allowance is the amount of mobile internet included in your plan.

It is normally shown in:

GB — gigabytes

For example:

5 GB

20 GB

100 GB

or:

Unlimited

The more data included, the more you can use away from Wi-Fi.

However, bigger is not always better value.

How Much Data Do You Need?

This depends on how you use your phone.

For example, browsing websites and sending messages normally use much less data than streaming video.

Likewise, if you spend most of your time connected to Wi-Fi, you may use relatively little mobile data.

Therefore, check your current use before choosing your next contract.

Ask:

How much data do I normally use each month?

Then choose an allowance with enough room for normal changes.

Don’t Pay for Data You Never Use

Suppose your contract includes:

100 GB

However, you normally use:

8 GB

In that case, most of your allowance is going unused.

Therefore, a smaller and cheaper plan may be enough.

On the other hand, choosing too little data could lead to extra charges or inconvenience.

So, aim for a sensible balance.

What Does Unlimited Data Mean?

Unlimited data means there is no normal fixed monthly data allowance.

This can be useful for heavy users.

For example, it may suit someone who regularly streams video or uses their phone as a hotspot.

However, check the terms.

Some plans may have rules around very high use, tethering or roaming.

Therefore, don’t rely on the word unlimited alone.

Check what is actually included.

What Are Minutes and Texts?

Most modern contracts include a large number of UK minutes and texts.

Many include unlimited UK calls and texts.

However, that does not mean every possible call is included.

For example, some:

  • Premium numbers
  • International calls
  • Directory services
  • Special-rate numbers

may cost extra.

Therefore, if you regularly call numbers outside normal UK allowances, check the charges.

What Is an eSIM?

An eSIM is a digital version of a SIM card.

Instead of inserting a physical card into the phone, the mobile service can be added electronically.

This can make changing or adding mobile services easier.

However, not every handset supports eSIM.

Likewise, support varies between providers.

So, check compatibility first.

What Is a Dual-SIM Phone?

Some phones can use two mobile connections.

For example, you could have:

Personal number + Work number

or:

UK SIM + Travel SIM

This can be useful if you want to keep two numbers without carrying two phones.

However, the exact features depend on the handset.

Therefore, check how dual SIM works on the phone you are considering.

Check Network Coverage First

A cheap contract is poor value if you cannot get a reliable signal.

Therefore, check coverage before choosing a network.

Think about the places where you regularly use your phone.

For example:

Home

Work

Family homes

Regular travel routes

and:

Places you visit often

One network may work extremely well in one location but poorly somewhere else.

So, don’t choose using price alone.

4G and 5G

Most modern contracts include access to 4G.

Meanwhile, many also include 5G.

5G can provide faster data where coverage is available.

However, you need:

A 5G-capable phone

and:

5G network coverage

If either is missing, your phone will normally use another available network technology instead.

Therefore, check coverage rather than paying extra simply because a plan mentions 5G.

Check Indoor Coverage

Outdoor coverage maps are useful.

However, indoor coverage can be different.

For example, mobile signals can be weakened by:

  • Thick stone walls
  • Concrete
  • Metal
  • Insulation
  • The position of the building

Therefore, local experience can be useful too.

If you know a particular network works well inside your home, that is valuable information when comparing contracts.

What Is Wi-Fi Calling?

Wi-Fi Calling allows compatible phones to make and receive calls using a Wi-Fi connection.

This can help where indoor mobile coverage is poor.

For example, you may have a weak mobile signal inside your home but excellent broadband.

In that situation, Wi-Fi Calling can make a big difference.

Therefore, if you have poor indoor coverage, check whether both the network and your phone support it.

Can the Monthly Price Increase?

Yes, depending on the contract.

Therefore, do not assume that the starting monthly price will stay the same.

Importantly, Ofcom changed the rules for new contracts from 17 January 2025.

Where a provider includes an in-contract price rise, it must now show the increase clearly in pounds and pence when you sign up, rather than relying on an uncertain inflation-linked formula.

So, check:

What will I pay now?

When will the price rise?

and:

What will I pay afterwards?

Calculate the Cost After Price Rises

Suppose your contract costs:

£25 per month for 12 months

Then it rises to:

£28 per month for the next 12 months

First:

£25 × 12 = £300

Then:

£28 × 12 = £336

Therefore:

£300 + £336 = £636

Now add any upfront payment.

That gives you a much better idea of the real contract cost.

What Happens When the Contract Ends?

When your minimum contract ends, your mobile service does not normally stop.

Instead, it usually continues.

However, you should check what you will pay after the minimum period.

This is particularly important with handset deals.

If the handset has been fully paid for, make sure you understand what happens to the rest of the monthly payment.

Ofcom requires providers to send customers information when contracts are coming to an end and to remind customers who remain out of contract about available deals.

So, don’t ignore an end-of-contract notice.

It is a good time to compare.

Don’t Keep Paying Without Checking

Once your minimum contract ends, review your options.

First, check whether the phone is paid for.

Next, look at your current monthly charge.

Then, compare SIM-only deals and other options.

If your phone still works well, keeping it could save you money.

There is no need to replace a handset simply because the contract has ended.

Can You Leave a Mobile Contract Early?

Usually, yes.

However, you may have to pay an early termination charge if you are still within your minimum term.

If you have a separate handset finance agreement, you may also need to pay the remaining device balance.

Therefore, check the cost before switching.

Sometimes, a new deal looks cheaper but becomes more expensive once the exit cost is included.

Check Your Exit Cost Before Switching

You can ask your provider what it would cost to leave.

This is useful because it gives you a clear figure.

Then you can compare:

Cost of staying

against:

Cost of leaving + New contract

That helps you make a better decision.

Can You Keep Your Mobile Number?

Yes, in most cases.

You can normally take your number to another mobile provider.

To do this, you need a:

PAC — Porting Authorisation Code

The process is designed to be simple.

How Do You Get a PAC Code?

Text:

PAC

to:

65075

Your current provider should then send you the information you need to switch while keeping your number. Ofcom introduced this Text-to-Switch process to make changing mobile providers easier.

Next, give the PAC to your new provider.

It will then arrange for your number to move across.

What If You Don’t Want to Keep Your Number?

You can request a:

STAC — Service Termination Authorisation Code

Text:

STAC

to:

75075

This is useful if you want to leave your current provider but do not want to take the old number with you.

So, remember:

PAC = Keep your number

STAC = Don’t keep your number

Want Information Before Deciding?

You can also text:

INFO

to:

85075

This can give you useful information about your existing contract without starting the switching process.

Therefore, it can be a useful first step if you are simply considering your options.

Don’t Cancel First if You Want Your Number

If you want to keep your existing mobile number, do not cancel the service first.

Instead:

Choose your new deal

↓

Get your PAC

↓

Give the PAC to your new provider

↓

Let the providers arrange the transfer

This reduces the risk of losing your number.

How Long Does a Number Transfer Take?

Mobile number transfers are normally quick.

Ofcom’s switching rules require providers to complete the port within one working day once the process is ready to go.

However, occasional problems can happen.

Therefore, keep the old SIM until the transfer is complete.

Then check that calls, texts and mobile data are working correctly.

What About Roaming?

Roaming means using your mobile service while abroad.

Do not assume that roaming is included.

Instead, check before travelling.

Look at:

  • Countries included
  • Daily charges
  • Data limits
  • Call charges
  • Text charges
  • Fair-use rules

The cost can vary significantly between providers and destinations.

Therefore, check the rules for the country you are visiting.

Is EU Roaming Still Free?

Not necessarily.

Some UK providers include roaming in parts of Europe.

Others charge for it.

In addition, different plans from the same provider may have different rules.

Therefore, never assume that European roaming is automatically free.

Check your own contract before travelling.

Watch Out for Roaming Outside Europe

Charges can be much higher in some countries outside Europe.

Therefore, check before using mobile data.

You may have several options.

For example:

  • Buy a roaming add-on
  • Use Wi-Fi
  • Use a local SIM
  • Use a travel eSIM
  • Turn mobile data off

The best option depends on the destination and how much data you need.

What Is Tethering?

Tethering lets another device use your phone’s mobile data connection.

For example, you can turn your phone into a Wi-Fi hotspot and connect a laptop.

This can be very useful when travelling.

However, laptops can use much more data than phones.

Therefore, keep an eye on your allowance.

Also check whether your contract has any limits on hotspot use.

Spending Caps

Some contracts allow you to set a spending cap.

This can help control charges outside your normal allowance.

For example, it may help prevent unexpected spending on:

  • Extra data
  • Certain calls
  • Some roaming charges
  • Other chargeable services

Therefore, if you want more control over your bill, ask about spending caps.

Think Carefully About Phone Insurance

A mobile contract may offer insurance alongside the handset.

This can provide useful protection.

However, don’t automatically add it.

First, check:

What does it cover?

What is the excess?

Are there exclusions?

Do I already have cover elsewhere?

For example, your phone may already have some protection through another insurance policy.

So, check before paying for duplicate cover.

Watch Out for Extras

A mobile deal may include additional services.

For example:

  • Music subscriptions
  • Video streaming
  • Cloud storage
  • Security software
  • Insurance

Some may be useful.

However, others may become chargeable later.

Therefore, ask:

Is this really free?

How long is it free for?

What happens afterwards?

Then cancel anything you do not want before charges begin.

Buying a Phone Separately

You do not have to get your phone from your mobile network.

Instead, you can buy a handset separately and then choose a SIM-only plan.

This makes it easier to see:

Phone cost

and:

Mobile service cost

separately.

It can also make future switching easier.

However, compare the total cost because a bundled handset deal can sometimes still be competitive.

Refurbished Phones

A refurbished phone can be another option.

These are previously owned devices that have been checked and prepared for resale.

They can cost much less than new models.

Therefore, combining a refurbished handset with a SIM-only contract can sometimes provide very good value.

However, check:

  • Condition
  • Warranty
  • Battery health
  • Seller reputation
  • Return rights

Then compare it with buying new.

Do You Really Need a New Phone?

This is one of the most useful questions to ask.

If your current phone still works well, you may not need another one.

Instead, you could:

Keep the phone

and:

Move to a cheaper SIM-only deal

This may save a significant amount over a year.

In addition, keeping devices for longer reduces electronic waste.

So, it can be better for both your finances and the environment.

What If You Change Your Mind?

If you buy a mobile contract online or over the telephone, consumer cancellation rights will normally give you a 14-day cooling-off period.

However, the exact position can depend on how the contract was arranged and whether services have already been used.

Therefore, check the cancellation terms before agreeing.

If a handset was included, you may also need to return it in the required condition.

Mobile Contracts for Businesses

Business mobile contracts can work differently.

For example, they may include:

  • Several mobile numbers
  • Shared data
  • Central billing
  • Business support
  • International services
  • Device management
  • Longer agreements

Therefore, businesses should check the terms carefully.

In particular, look at:

Contract length

Number of connections

Price changes

Data allowances

Exit terms

and:

Overall cost

A low price per SIM does not automatically mean the whole contract offers good value.

Compare Mobile Phones

Energility is developing its mobile comparison service.

Our aim is to help you compare more than just the headline monthly price.

Instead, we want to help you look at:

Handset cost

Monthly cost

Data

Network

Contract length

Future price changes

and:

Total cost

Coming Soon

Our Compare Mobile Phones service is planned to launch in January 2027.

However, you can still use our mobile guides in the meantime.

They can help you understand mobile contracts and prepare for your next comparison.

Before Choosing a Mobile Contract

Use this simple checklist.

  • Do I actually need a new phone?
  • Could I keep my existing handset?
  • Would SIM only be cheaper?
  • How much data do I really use?
  • Does the network have good coverage?
  • Does it work well inside my home?
  • How long is the contract?
  • Is there an upfront payment?
  • Will the monthly price rise?
  • What is the total contract cost?
  • What would it cost to leave early?
  • Is roaming included?
  • Can I use tethering?
  • Are there any extra services?
  • Do I need the insurance?
  • Can I set a spending cap?
  • Can I keep my number?

Once you know the answers, comparing contracts becomes much easier.

A Simple Way to Compare Mobile Deals

Start with the phone.

Do you need a new one?

If not, look at SIM-only deals first.

Next, check your data use.

How much do you actually need?

Then, check network coverage.

After that, look at the contract length and monthly cost.

Next, include any upfront payment and planned price rises.

Then calculate the total cost.

Finally, check roaming, exit charges and any extras.

This gives you a much clearer comparison than simply looking at the monthly price.

Quick Summary

Mobile contracts do not need to be complicated.

First, decide whether you need a new phone.

If your existing handset still works well, a SIM-only deal may save money.

Next, check how much data you actually use.

Then, make sure the network works well where you need it.

After that, look at the contract length.

Meanwhile, check any future price rises and upfront costs.

Then calculate the total amount you will pay.

If you decide to switch, you can normally keep your number by getting a PAC code.

Finally, check any roaming charges, extras and exit terms before agreeing.

Most importantly:

Do not judge a mobile contract by its monthly price alone.

Instead, choose a deal that gives you the right balance of coverage, data, flexibility and total cost.

Energility

Understand More. Spend Less. Live Better.