Seven things to check before you sign a new mobile phone contract

Taking out a mobile contract isn't as simple as it used to be.As well as a wide range of handsets and providers to choose from, there's also the lure of big discounts on handsets that might make a Sim-free purchase seem like a better deal.

If you're tempted by one of the many discounts and the lure of a shiny new handset, check our advice before before you sign on the dotted line.

Check our guideto the best mobile phone and Sim-only deals, or head on over to Which? Switch Mobile to see the best Sim-only and contract phone deals.

1. Upfront costs and data allowance

While you might see a temptingly low monthly fee advertised for a flashy new handset, an upfront cost could run into hundreds of pounds for high-end phones.

Essentially this means you're purchasing a proportion of the handset up front and spreading the rest over the contract - so the headline monthly cost might be misleading.

Also be wary of high data allowances - these are often sold as 'great deals', and can includes offers such as double the data. Consider how much data you really need, so you don't end up paying for something you won't use.

Add the upfront cost and your typical data allowance into our mobile phone cost calculator to see if you're better off buying on contract or Sim-free.

2. Potential price rises

Check those T&Cs. Many mobile networks have recently introduced yearly above-inflation price rises in their contracts, meaning that you will see a yearly increase of around 5 - 7% on your contract. While not a lot in isolation (7% on £50 would be £3.50 extra a month), these costs can add up, particularly depending on when you take out your contract.

Therefore, if you want to make sure that the price you are paying for stays consistent, you are better off finding a provider which does not bake in price rises and ideally, has a 30-day airtime contract to give you flexibility of changing if price rises are brought in. Browse the best Sim-only deals to see what's on offer.

3. Mobile coverage

If you think you have found the right deal with the right provider, don't forget it's important to know you'll get good coverage, not just at home, but also at your places of work and other areas you like to regularly go to.

Our 3G, 4G and 5G coverage map has coverage information at a postcode level and can tell you how good the coverage is in that area.

If you're moving to a provider on the same network to one you're currently using, you'll already know whether reception is good, or needs improving. Check the table below to find out which signal your provider uses.

If you want to be extra sure that reception is good before you enter into a lengthy contract, try picking up a cheap pay-as-you-go Sim from the network in question and trying it out first.

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4. Contract length

With phones getting pricier, many people are turning to longer contracts in order to make the monthly price lower. It's important to check contract length carefully, as what might look like a low monthly fee may not be as appealing if you're tied to it for 36 months instead of 24 - you may end up paying more money in the long run.

For example, at the time of writing, Virgin Mobile is offering an iPhone 12 Pro with a 12GB plan for £55 a month on a 24-month contract, which works out to a total of £1,320. The same phone and deal on a 36-month contract would cost £40 a month, which works out to a total of £1,440 - £120 more.

Also, be sure to keep an eye on the contract end date and whether you get an end-of-contract notification, which can help you avoid being overcharged for your mobile phone.

5. Roaming costs

With both Vodafone and EE recently announcing the return of mobile roaming charges in the EU, it's worth checking what your provider's roaming plans are, and in general how much it costs to use your phone in a country you're travelling to.

Outside of the EU, the costs can be much higher - you can pay as much as £42 just to stream one song on your favourite streaming app. If roaming is important to you, consider opting for a monthly Sim-only contract with a roaming-friendly provider.

Currently, no other mobile providers have made plans to start charging for roaming in the EU. But with two big providers announcing changes, others could follow suit.

Find out more about mobile roaming and how to prepare your phone for holidays abroad.

6. Flexible contracts

Some mobile providers, like Vodafone with its new EVO proposition and O2 with Refresh, have introduced flexible contract lengths from 12 to 36 months.

While this flexibility may be attractive to some, you may actually end up paying more by restricting your choice to these providers.

Ultimately, you have to decide whether price or flexibility is the most important factor in choosing your next mobile contract, and how important it is that you always have the latest handset.

7. Price isn't everything when it comes to a good mobile contract deal

While having a cheap deal is certainly one of the most important factors in choosing a contract, it should not be the only one.

Are you someone who likes to speak to a human when you have an issue? Then Giffgaff is not for you.

Want extra incentives and rewards such as cinema tickets or discounts on food and drink? You may want to check out the bigger name providers.

Our annual mobile networks analysis takes into account all these factors and more, including price, to determine who are the best and worst mobile networks. Make sure you check out our guide to the best and worst mobile providers to see where your potential new provider is in the rankings.