We round up the best SIM-only tariffs boasting unlimited data (or as close as possible), from the biggest UK mobile providers: TalkTalk Mobile, Three, Vodafone, EE, Virgin Mobile, O2, BT, Giffgaff and Tesco Mobile.
What is a SIM-only phone contract and where can I buy one?
SIM-only deals do exactly what they say on the tin - these are mobile phone contracts that only give you the SIM card. You don't get a subsidised smartphone with a SIM-only contract, but you do generally speaking get more minutes and messages for your money as a result.
All you need to do is buy a phone from an online retailer, if you don't have one already, and then choose the best SIM-only deal for you. Your SIM card will then be posted out to you, at which point you stick it in your mobile and away you go.
You can also choose between 12-month and 30-day SIM-only contracts. The 12-month contracts tend to offer more data and minutes for a smaller monthly fee, but you're stuck in that contract for a full year. A 30-day rolling contract is more flexible as you can quit at any time, but you tend to get less for your monthly fee.
If you're still spotty on the details, check out the video we've put together and read on to get the lowdown on the best SIM-only deals in the UK right now. You can also use our SIM-only comparison tool if you're tempted by any of the offers, to make sure you're getting the best possible deal.
Which is the best SIM-only deal: O2 - 'Unlimited' not available, £28 a month for 16GB
|12 Months||25GB||Unlimited||£26.00 Per Month|
|30 Day Rolling||8GB||Unlimited||£21.00|
O2 doesn't offer 'unlimited' data on SIM-only contracts, so the closest thing you'll find is its 12-month SIM-only deal which offers 25GB of data, plus unlimited minutes and texts, for £26 a month. You also get full 4G support for that, which is good news if you're streaming a lot of Netflix on the move, as well as free O2 WiFi and daily offers with the Priority service.
O2 also offers a 30-day rolling SIM-only plan with a promotional cost of £21 per month, which gives you 8GB of data. The benefit is that you can cancel at any time and move to another operator if you spy a better deal.
Check out the O2 SIM-only deals page for more info.
Which is the best SIM-only deal: Three - From £23 a month for unlimited
|12 Months||30GB||Unlimited||£20.00 Per Month|
|12 Months||Unlimited||Unlimited||£28.00 Per Month|
|30 Days Rolling||30GB||Umlimited||£24.00|
|30 Days Rolling||Unlimited||Unlimited||£32.00|
Three's all-you-can-eat SIM-only deals start at £28 a month, and for that you get unlimited texts and minutes per month on a 12-month contract, with full 4G streaming included.
If you want the flexibility of a 30-day rolling contract, you'll need to bump that up to £32 per month. That also bags you unlimited texts and minutes to use each month.
These plans also include the usual roaming, personal hotspot allowance of up to 30GB and the new Go Binge service.
Which is the best SIM-only deal: TalkTalk Mobile - 'Unlimited' not available, £7.75 a month for 2.1GB
At the time of writing, TalkTalk Mobile is no longer offering any kind of phone contracts, SIM-only or otherwise, to new customers. This is because they're updating their service.
Check out the TalkTalk Mobile SIM-only deals page for more info and the new deals when they become available.
Which is the best SIM-only deal: Giffgaff - £20 a month for unlimited data
|30 Days Rolling||Unlimited UK Data||Unlimited||£20.00|
|30 Days Rolling||6GB UK Data||2000||£18.00|
Giffgaff, which runs on O2's network, calls its SIM-only plans 'Goodybags'. The £20 per month Goodybag gives you 'Always On' data (so you can browse and stream to your heart's content) as well as unlimited texts and calls.
You get 4G data speeds as standard too, so that won't cost you anything extra and you should happily be able to stream YouTube cat videos as much as you like - providing you're not residing in a signal black hole. Ta very much!
Check out the GiffGaff SIM-only deals page for more info.
Which is the best SIM-only deal: EE - 'Unlimited' not available, £34.99 a month for 16GB
|12 Months||16GB||Unlimited||£34.99 Per Month|
|30 Day Rolling||6GB||Unlimited||£27.99|
EE doesn't offer straight-up 'unlimited' SIM-only deals, but you can get a 16GB 12-month contract for £35 a month. That's as good as unlimited unless you're streaming HD movies all day long, although it's also not the cheapest SIM-only offering here. Of course, EE does boast strong national coverage, while its 'double speed 4G' network offers LTE-A speeds that exceed rivals.
If you want the freedom of a 30-day rolling contract, the biggest data package you can bag from EE is 6GB per month for £27.99. Both the 12-month and 30-day deals give you unlimited minutes and texts too.
UPDATE: Until August 13 2017, EE is offering 30GB of data per month on its 30-day rolling contract, for just £15. That's a saving of 50 percent off the standard price. You can see more info on this deal at HotUKDeals.
Take a look at EE's SIM-only deals page for more info.
Which is the best SIM-only deal: Vodafone - 'Unlimited' not available, £25 a month for 25GB
|12 Month||20GB||Unlimited||£22.00 Per Month|
|12 Month||40GB||Unlimited||£40.00 Per Month|
|30 Day Rolling||10GB||Unlimited||£29.00 Per Month|
If you want to limit yourself to a 30-day rolling contract, Vodafone's 10GB Plan is the best you'll manage. For £29 a month you get 10GB of 3G or 4G data, plus 500 minutes.
Knock that up to a 12-month contract and you can get up to a whopping 20GB of monthly data for £22 a month - or 40GB for £40 per month - on the Red Value deal, at the time of writing. This also bags you a Now TV, Spotify or Sky Sports Mobile TV subscription for the full 12 months.
Check out Vodafone's SIM-only deals page for more info.
Which is the best SIM-only deal: Virgin Mobile - 'Unlimited' not available, £23 a month for 10GB
|30 Day Rolling||10GB||Unlimited||£23.00|
For non-Virgin customers, the closest you'll get to unlimited data is the 10GB, 12-month SIM-only contract with unlimited minutes and texts for £20 a month. That drops to £19 a month if you go for a 12-month contract instead; not exactly a massive saving.
Have a gander at the Virgin Mobile SIM-only deals page for more info.
Which is the best SIM-only deal: TPO - ‘Unlimited’ not available, £20 a month for 6GB
|12 Months||6GB||2400 Minutes||£20.00 Per Month|
|12 Months||5GB||1200 Minutes||£18.00 Per Month|
TPO (The People’s Operator) offers customers 4G broadband services on a range of SIM-only deals. It uses EE’s network, which means the great majority of folks with a TPO SIM should be able to enjoy double digit download speeds on the go.
While TPO doesn’t offer any unlimited data plans yet, they do offer 6GB for £20 a month. That's sadly jumped up in cost a lot these past few months, from just £12.50 a month.
Those who perhaps don’t need that much data can get a 5GB deal for £18 a month, or 4GB for £15 a month.
Have a squint at the TPO SIM-only deals page for more info.
Which is the best SIM-only deal: Tesco Mobile - 'Unlimited' not available, £30 a month for 20GB
|12 Month||20GB||5000 Minutes||£20.00 Per Month|
|1 Month Rolling||12GB||5000 Minutes||£28.00 Per Month|
Tesco's best SIM-only deals include 20GB of 4G data for £20 per month. That also nets you 5000 minutes and 5000 texts, and lasts for 12 months.
Fancy the flexibility of a 30-day rolling contract instead? On Tesco Mobile, the most data-packed rolling deal you can get is just £28 a month but you only get 12GB of data, with 5000 minutes and texts.
Check out the Tesco Mobile SIM-only deals page for more info.
Which is the best SIM-only deal: BT Mobile - 'Unlimited' not available, £21 a month for 20GB for non BT customers
|12 Months (For BT customers)||15GB||Unlimited||£21.00|
|12 Months (For Non BT Customers)||15GB||Unlimited||£25.00|
You can jump onto BT's new network with SIM-only plans starting at just £5 per month (if you're a BT customer already; £10 per month otherwise), but if you want a shedload of data you'll have to stump up some more cash.
BT customers can get a 20GB 12-month SIM-only contract for £16 per month, with unlimited calls and texts. If you're not on BT, that same deal will cost you £21 per month.