Over the past few years, SIM-only contracts have seen something of a resurgence in the consumer market. There are at least two reasons for this. Firstly, carriers (or networks) don't make much money on selling phones, and so they can make practically pure profit from selling you a SIM-only contract.
Secondly, consumers have watched as regular contract tariffs monthly costs have grown from around £35 per month to almost £50 pre month. SIM-only then, is much more affordable than a conventional phone+line contract.
SIM-only can often be the best way to get great value for money, especially if you already have a phone, or if you'd rather buy your unlocked phones direct from manufacturers.
UK network coverage checkers
In each of the categories we'll break down offerings available from the UK's big four networks as well as some of the more popular MVNO's like GiffGaff, BTMobile and such. However, it is worth checking which carrier has the network coverage you need. After all, there's no point snagging yourself a stonking deal if you can't use the allowances you're paying for.
Below you'll find links to the four coverage checkers you need. Why four? Because any other network is an MVNO (Mobile Virtual Network Operator), which means they don't have their own masts and signal, they use the networks provided by Vodafone, EE or O2. GiffGaff and Tesco mobile, for instance, uses O2's network, while BT Mobile uses EE's.
Best SIM-only plans: the cheapest available
If you're a very light user and literally just want the most dirt-cheap contract available, you'll have little reason to spend more than £10 per month. Most network operators have deals available that cost less than a steak dinner.
Unless otherwise stated, all plans are 12-month contracts (since that's how you get the lowest monthly costs), allowances listed are UK only and up to 4G speeds.
- BT Mobile - £10 per month (£5 for BT broadband customers) - 200 mins - unlimited texts - 500MB data
- Virgin Media - 30 day rolling plan - £5 per month - 250 mins - unlimited texts - 250MB data
- GiffGaff - 30 day rolling plan - £5 per month - 125 mins - 500 texts - 100MB data
- Tesco Mobile - £7.50 per month - 250 mins - 5000 texts - 500MB data
- Three - £8.00 per month - 200 mins - unlimited texts - 500MB data
- Vodafone - £9.50 per month - 250 mins - unlimited texts - 250MB data
- EE - £9.99 per month - 250 mins - unlimited texts - 250MB data
- O2 - £10.00 per month - 250 mins - unlimited texts - 250MB data
If you're a BT broadband customer, there's very little reason to choose anyone other than BT Mobile. For £5 per month you'll get half a gig of data as well as unlimited texts and 200 minutes.
If you're not a BT broadband customer, other options could include Tesco Mobile's £7.50 per month one year contract with half a gig of data, 250 minutes and 5000 texts, or there's Virgin Media and GiffGaff who both offer a £5 per month 30-day rolling plan.
Of those two, Virgin Media's is easily the most competitive offer since GiffGaff only includes 100MB data, 500 texts and 125 mins. With that said, for just £2.50 per month more you can get yourself 500GB data, with unlimited texts and 250 minutes.
Arguably however, Virgin Media's next tariff up is better value for money. For £8 per month you can get a whole 1GB of data each month as well as 1000 minutes and unlimited texts. This is all on a plan that only ties you in for 30 days at a time.
Best SIM-only plans: with the most data?
If you're a Pokemon Go addict, or are constantly connected and streaming videos on the go, you just want as much data as you can get. Amazingly, for just over double the price of the cheapest available tariffs, you can get more data than you'll possibly need.
- Three - Unlimited data - £23/£28/£33 per month for 200/600/Unltd minutes - (+30GB hotspot allowance)
- Vodafone - 20GB data - £22.20 per month
- Tesco Mobile - 20GB data - £29 per month
- O2 - 16GB data - £28.90 per month
- BT Mobile - 15GB data - £21 per month (£16 per month for BT Broadband customers)
- Virgin Media - 10GB data - £23 per month - 30 day rolling agreement
- EE - 8GB data - £27.99 per month
- GiffGaff - Always on* - £20 per month - 30 day rolling agreement - (*speed restrictions after 6GB usage)
Unsurprisingly, Three are the kings of data. The disruptive carrier has been one of the few offering unlimited (all-you-can-eat) data for the past few years.
Depending on how few minutes you can live with, you can get unlimited data from Three from as little as £23 per month. And because it's on Three's Advance plans, you can use your allowances abroad in more than 40 countries. Plus, you get a 30GB allowance for tethering, in case you need to use your phone as a hotspot.
We're hesitant to recommend GiffGaff's "Always On" data, since you get penalised if you use more than 6GB, which is nothing close to unlimited. That means, surprisingly, Vodafone comes as our next recommendation after Three with its 20GB plan, which comes in at £22.20 per month and includes 4GB of data to use abroad in 40 countries.
Best SIM-only plans: for roaming?
So you travel abroad a few times each year and you want to stop coming home to a bill filled with additional roaming charges. Thanks to the impending EU-wide abolition of roaming charges, carriers are already working on hard on getting the competition going.
- Three - Feel at home on the Three Advanced plans lets you use your allowances in 18 countries abroad (more than 40 from September)
- Vodafone - several plans include unlimited roaming minutes and texts plus some roaming data for use in 40 European destinations
- EE - EE Extra plans come with unlimited mins and texts in Europe, £3 per day for 500MB data just text EURODATA to 150
- Tesco Mobile - plans include European Roaming in 31 countries
- O2 - O2 Travel bolt-on costs £1.99 per day in EU, £3.99 in Turkey and £4.99 in other destinations - 120 mins/texts and data
- Virgin Media - Extra charges depending on country plus extra data bundles
- GiffGaff - Extra charges depending on country
- BT Mobile - Extra charges depending on country
Of all the offerings, Three, Tesco Mobile and Vodafone offer the most seamless experience when it comes to taking your phone overseas. Voda's 12-month SIM-only plans all include unlimited minutes, texts and picture messages in 40 EU destinations, while many plans come with 4GB data to use abroad.
Three's "Feel at Home" is the mostly widely advertised and is still, arguably the best offer for travellers. On its Advance plans from September, customers can use their allowances in over 40 countries across the globe, not just in Europe. Those include popular holidaying countries like the US, Australia, Spain, France, Italy and many others.
Tesco Mobile deserves a mention, since its SIM-only plans include roaming in 31 European countries.
Best SIM-only plans: for tablets and dongles
If you have an unlocked Wi-Fi dongle, data stick or SIM tray-equipped tablet and want to find the cheapest, best value for money way to stay connected on the move, you'll be pleased to know several carriers offer data only SIMs just for you. All the prices listed below are for 30-day contracts.
- Virgin Media - 500MB/1GB/2GB/4GB/8GB plans for £5/£8/£11/£14/£21 per month
- O2 - 500MB/1GB/3GB/15GB plans with 100 texts for £5/£10/£15/£20 per month
- Three - 2GB/5GB/15GB/20GB plans for £10/£15/£20/£23 per month
- Vodafone - 1GB/3GB/10GB plans for £10/£15/£20 per month
- GiffGaff - 500MB/1GB plans for £5/£7.50 per month
- BT Mobile - No data-only SIMs available
- Tesco Mobile - No data-only SIMs available
- EE - Nothing without buying a WiFi dongle or tablet
As far as competition goes, it's GiffGaff, O2 and Virgin Media that offer the cheapest monthly options at just £5 per month. Those only offer 500MB of data, but that could be enough if you just want to check the odd email, when you're in the rare spot that doesn't have Wi-Fi.
Three perhaps offers the most variation since the carrier sells their data plans as 12-month or 30-day options. The former cost roughly £2-£3 less than the 30-day rolling contract options, and also come with a 1GB data tier which is just £7.50 per month. Three's 2GB deal looks a safe bet, especially at just £10 per month (or £8 per month on a one year plan).
Perhaps be-musingly, EE don't sell monthly rolling contracts for data-only SIMs online (unless they've been hidden out of sight). It sells tablets and personal hotspots on contract, but doesn't sell the data plans with just a SIM. Similarly, BT Mobile and Tesco Mobile don't offer data-only plans.