How to find the best mobile phone tariffs

There’s always so much to consider when getting a new phone. Should you go for the latest iPhone, opt for a sleek Samsung or give the latest Google phone a bash? But, even if you have your heart set on a phone model, there’s still endless phone plans for you to choose from. We are here to help get the best mobile phone tariff for you...

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How to run a mobile tariff comparison

The best way to find a good mobile phone deal is to run a comparison. And the easiest way to do this is to let a dedicated comparison website, like, do the hard work for you. 

Choosing your phone tariff type

The first thing you need to consider before you even start looking for deals, however, is which type of plan you are looking for. These basically break down to:

Pay monthly

This phone tariff sets you up for a fixed duration, usually 12, 24 or 36 months on a handset plan and 1 – 36 months on a SIM-only plan. As the name suggests, a pay monthly phone tariff means that you pay once a month for your data use and to pay off the handset if you purchased them together. Leaving a pay monthly mobile contract early can be tricky, as can decreasing your data allowance mid-contract. Both of these things should be taken into consideration when looking at contract lengths and data allowance.

Even with these constraints, pay monthly contracts are a very popular choice, as they also break down the cost of some premium phones, say, the iPhone 12, to a more affordable monthly price than buying it outright. 

Pay as you go

Pay as you go is exactly that – you pay for a certain amount of credit, say, £10, and you can use your phone for calls, text and data until that £10 is used up, then you just top up again. There are a few variations to this such as the plans offered by VOXI and SMARTY. Both are technically pay as you go, but you pay for a set package of calls, texts and data outright, they last one month and then you pay again – or move onto a different network if you prefer.

If you’re on a pay as you go contract, you’ll need to make sure you don’t run out of credit. But on the flip side, they grant much more freedom compared to contracts and you can switch networks anytime provided your phone is unlocked. 

What to look for when you compare mobile phone tariffs

So, you’ve chosen what type of plan you want - here’s what else you should look out for.

Data allowances

Providers of both pay as you go and pay monthly plans will offer a range of data allowances. Your data allowance is the total amount of calling minutes, texts and browsing data you’re assigned each month. If you go over your allowance, you may face extra charges, or you will have to top up and this can get expensive in the long run. The counter to this is paying too much for data that you simply don’t use. Getting the balance right here is tricky, but worth it in the long run. 

Unlimited calls and texts are increasingly becoming the standard on pay monthly plans, and even on many pay as you go one-month packages like those described above. The main area for you to consider is your mobile data. You need data for just about everything you do on your smartphone, including:

  • Sending/receiving emails

  • Downloading files

  • Streaming

  • Uploading and sharing images and files

  • Instant messaging

  • Gaming

  • Web notifications like news headlines or weather

Basically, without a data allowance or Wi-Fi connection, your smartphone can’t be smart. Many networks offer unlimited data but this might not be the best choice for you. Yes, you need data, but you don’t want to pay for gigabytes you’ll never use. A good middle ground is around 10GB if you use your phone for all of the above on a daily basis when you’re out and about. If you depend on home broadband or work Wi-Fi for most of the day, you could get away with far less, say around 5GB. Heavy users who depend on data over Wi-Fi will want to look at higher numbers like 20GB or more.

As mentioned, it’s easy to up your data allowance. Most networks let you adjust your plan online without needing to talk to anyone, but it will be a lot harder to bring your monthly allowance down. Start small, and if you find yourself often needing more data, adjust your plan accordingly. It’s better to use what you pay for than pay for something you never use.

Contract duration

Phone contract lengths vary, but 24 months is the standard for most handset deals. For SIM-only deals you can be contracted for just 30 days, so it’s much easier. Contracts can be as long as three years, and while that may suit you as you’re looking for a long-term phone, consider the following:

  • Ease of upgrade

  • Price jumps

You may love your phone now, but if something newer, shinier and altogether better is released in a year’s time (and it almost certainly will be), you might be tempted to upgrade. So it’s easy to upgrade even if you lock into a long-term contract. O2, for example, offers a special plan that charges you separately for your data use and your handset. So you can fully pay off your outstanding handset balance whenever you like and switch to a newer device. 

Price jumps also occur once a year for inflation and pretty much all the main providers are guilty of this. The jump isn’t much - just 2-3% - but if you’ve been a customer for three years, you may have to face three price rises. Only Tesco Mobile, as of February 2021, has promised to not introduce these price rises. 

Upfront cost

The more you can pay for your phone upfront, the smaller your monthly costs should be, so it helps to save up those extra pennies. The total you have to pay can vary hugely from network to network and plan to plan, so this is also why shopping around is key. If you find a contract that has a strangely low monthly fee, then it is worth checking the upfront cost as this is likely to be much higher. 


Some networks will give you the flexibility to adjust your plan. Tesco Mobile and O2, for example, let you pick precisely how long you want your contract to be, how much data allowance you want each month and what you want to pay upfront. This is ideal if you’re working for a strict budget or a rigid timeframe where 12 months is too short and 24 months is too long. Both providers also offer pre-set plans if you prefer, but having this element of freedom may be just what you need in your circumstances. 


Pay as you go and pay monthly plans are, as of February 2021, still covered for free EU roaming, but with the UK now out of the EU, there’s no knowing how long this will last. EU roaming aside, if you’re a frequent traveller you’ll want to pay attention to each network’s overall roaming offering. Vodafone probably takes the lead here, as an international brand with a huge number of countries covered by roaming. Where your roaming destination isn’t covered as part of your plan, many networks will extend your coverage for a set price, such as Three and EE. Some, like O2, have additional locations on top of their standard EU countries on selected plans, covering New Zealand, Australia and the USA, among others. 

Customer perks

At, there are few things we love more than customer perks. And the ones that suit you best will entirely depend on your interests. For the music-lover, O2 offers priority access to gig tickets and venues. Even pay as you go one-month plans can come with great perks, so have a look at VOXI’s fun treats. Or if you want your monthly phone bill to get you some extra points towards your grocery shop, try Tesco Mobile. Of course, this shouldn’t be the most important thing to consider when it comes to finding the best phone plan, but if a free cup of coffee every now and then or a free subscription to your favourite streaming service makes a deal seem all the sweeter to you, then go for it.

Entertainment and other benefits

Free access to premium entertainment apps is generally reserved to pay monthly customers only, so pay as you go customers won’t be able to take advantage. That said, there are plenty of benefits like data-free social media or money-back plans from the likes of SMARTY that are definitely worth considering. 

Entertainment deals can save you a month or more on the cost of access to apps like:

  • BT Sport

  • Amazon Prime Video

  • YouTube Premium

  • Spotify Premium

These are often offered free for a set time, provided you buy an eligible plan. Usually access is around one month, but it can be six months or even a whole year. Considering access to these apps can be around £20 a month, that’s a huge saving, and all for the price of a phone plan you were buying anyway. 

Extra mobile phone charges

Keep an eye out for any extra charges that may be added to your plan, this includes:

  • Yearly price jumps

  • Extra fees for going over your monthly data limit

  • Extra fees for roaming 

  • Price per minute/text for pay as you go

Make sure you’re always aware of how much data you’re using, as you can easily rack up out-of-allowance charges. If you’re on pay as you go, you may also want to spend time looking at precisely how much you will pay per minute/text as these can vary hugely from network to network. In many cases, it’s better to buy a pay as you go bundle, as you get more for your money. But as these only last a month, if you aren’t a frequent caller it may not be worth it.

Pay as you go customers will also want to check how long their credit actually lasts, as, annoyingly, networks set a time period before your remaining credit is made void.

How long does pay as you go credit last?

Updated 17 July 2020
NetworkTime limit on PAYG credit
O26 months
VodafoneN/A (must use data once every 180 days)
Three6 months
EEN/A (must use data one every 270 days)
Tesco Mobile6 months
VOXI180 days
iD Mobile90 days
ASDA MobileN/A (must use data once every 6 months)
giffgaffN/A (must use data once every 6 months)


Price is very important, but so is the value of the overall contract. And you might decide to opt for a slightly pricier option if it comes with, for example, data-free streaming, better roaming, free entertainment and unlimited minutes.