Unlimited Data SIM Only Deals

What is an unlimited data SIM?

An unlimited data SIM is a plan that comes with unlimited data. They work much like any other SIM, but allow you to use as much data on your device as you want without worrying about running out or getting a big bill.

Typically, these plans will also come with an allowance of minutes and texts (often also unlimited), unless it’s a plan for a mobile broadband device, in which case the SIM card might just come with data.

Unlimited data SIMs are available as SIM-only plans, which just include your SIM card and allowances, usually on a 30-day or 12-month plan, or you can get a Pay Monthly plan with a phone included as well, and these usually tie you in for 24 months.

Then there are unlimited data Pay As You Go SIMs, which give you unlimited data for a period of time (usually 30 days) but don’t tie you into a contract. You can also get unlimited mobile broadband devices, or a data-only SIM, which is like a SIM-only plan but doesn’t include minutes or texts.

What’s so good about unlimited data?

An unlimited data plan is a great choice if you tend to use a lot of mobile data. This might be the case if for example you tether a lot, as devices like laptops and tablets can be more data-hungry than phones.

They are also essential if you download lots of big apps or other files using mobile data. A single mobile game for example can use up well over 1GB to download in some cases.

Those who stream a lot of video, such as Netflix shows, while away from a Wi-Fi connection can also benefit from unlimited data, especially if you want to stream in high quality. Different services use differing data amounts, but if you’re a media fiend then you’re sure to eat through a huge quantity.

And unlimited data can also be a good choice for peace of mind, so you know you’ll never run short. It means you never need to even think about data or check how much you have left, and if there’s ever an unforeseen event like your Wi-Fi going down at home, you’ll be well equipped to keep your gadgets online through tethering.

Do I actually need unlimited data?

Not everyone needs unlimited data, so figuring out whether you do or not is a good idea before committing to a contract.

If you’re watching on average more than around an hour of streamed video content from Netflix or elsewhere in the maximum available quality each day using mobile data, then you should get an unlimited data plan.

Video tends to be one of the biggest consumers of data, but if you’re constantly using mobile data throughout the day for other things, such as downloading apps, streaming music, video calls, and online gaming, then you might also want to consider an unlimited plan.

If not, then you would probably be fine with a 100GB plan or maybe even a lot less, according to your own usage. For a breakdown of how far different data allowances go, check out our how much data do I need guide.

Which networks offer unlimited data SIM deals?

Currently, in the UK 15 networks offer unlimited data SIM deals, which includes the four main UK networks (EE, O2, Three and Vodafone), along with 11 MVNOs that piggyback off other networks (Asda Mobile, GiffGaff, Honest Mobile, iD Mobile, Lebara Mobile, Lyca Mobile, Smarty, Spusu, Tesco Mobile, Talkmobile, and VOXI). Currently, the networks not offering unlimited data plans are Sky Mobile, 1pMobile, Talk Home, and ParentShield.

Three

Three offers truly unlimited data on SIM Only, Pay Monthly and Pay As You Go phone plans, as well as unlimited Mobile Broadband plans.

There are no speed restrictions and you can tether as much data as you like. All plans are also 5G ready at no extra cost, so you can enjoy superfast speeds when 5G comes to your area.

However, unless you’re on Pay As You Go, on a new Value or Complete plan, or signed up for a plan or upgraded before October 1st, 2021, you’ll have to pay to roam on Three. Though it’s affordably priced, at £2 per day in Europe and £5 per day for a selection of locations outside Europe. You can also only use up to 12GB of data per month when roaming.

Beyond these roaming restrictions there is currently no fair usage policy for unlimited data on Three.

Related reading: Three Coverage and Network Review

EE

EE offers unlimited data plans on SIM Only and with Pay Monthly phones.

Currently EE offers unlimited data SIM Only plans on a choice of 1-month, 12-month, and 24-month durations. They come with 5G data, as well as unlimited minutes and texts, but note that some of these plans cap your speeds at 10Mbps or 100Mbps.

If you go for a plan with a handset then you’re stuck at either 24 or 36 months, and some plans have the same speed restrictions.

Whether you go SIM Only or Pay Monthly with a handset, you can also get ‘Inclusive Extras’ with select plans.

You can choose either 1 or 3 extras (depending on the plan), and possible options include Apple Music, Apple Arcade, Apple TV+, TNT Sports on Discovery+, Netflix, Microsoft 365 Personal, Xbox Game Pass Ultimate, and a Roam Abroad Pass (which lets you roam for free in some places outside Europe, and removes the £2.47 daily European roaming charge). Note that not all of these benefits are options on every plan – you may only be offered a subset of them.

There are also plans that come with Apple One, which bundles subscriptions to Apple Music, Apple TV Plus, Apple Arcade, and includes 50GB of iCloud+ storage.

Those who have multiple plans on their account can also gift up to 100GB of data per month to another EE plan, which is good for those with children who run out of data.

There is a small premium to pay for choosing EE, but the network offers high average speeds and has more widespread coverage than most rivals. There are some slight fair usage terms though, with the network saying you shouldn’t use more than 600GB per month, or regularly tether more than 11 devices. There’s also a 50GB fair use limit when roaming.

Related Reading: EE Coverage and Network Review

O2

With O2, unlimited data is available on SIM Only and Pay Monthly handset plans, with 1-month, 12-month and 24-month options for SIM Only, and customisable contract lengths if you’re getting a handset.

There are no speed restrictions and they all come with 5G data included. Some plans also come with up to six months of an extra of your choice (with options such as Disney Plus, Amazon Prime, Audible, and more).

Free data roaming in Europe has a 25GB limit per month, however some plans also let you roam further afield. Plans also include unlimited tethering, so you can share internet with other devices over a personal hotspot.

O2’s fair usage policy states that you shouldn’t use 650GB of data twice within a six-month period, or regularly tether 12 or more devices.

Related reading: O2 Coverage and Network Review

Vodafone

Vodafone also offers unlimited data SIM Only and phone plans including the option for unlimited 5G data.

A choice of 2 plan types are available, each of which offers different maximum download speeds.

Unlimited plans offer speeds of up to 10Mbps (fast enough to stream HD video), and Unlimited Max plans offer the maximum available speeds with no restrictions, and are the only ones able to benefit from 5G speeds.

Tethering is included and you can use up to 25GB of data per month when roaming in 51 European countries (though in most cases you’ll still have to pay a £2.42 daily fee to use your allowances abroad). On plans with ‘Xtra’ in the name though roaming is free, and some of these unlimited plans also let you roam for free in additional locations, for 83 in total.

There is also the option to add an entertainment subscription to the 12 or 24-month Unlimited and Unlimited Max plans for an extra £8 per month, which gives you a choice of a subscription to Amazon Prime, Spotify Premium, or YouTube Premium for the duration of the contract. Entertainment packages are also available on Pay Monthly with a handset.

Vodafone now also has an unlimited Pay As You Go plan. It’s a 5G plan, and you will also get VeryMe Rewards on all plans – which include things like free movie rentals and tasty treats.

Related Reading: Vodafone Coverage and Network Review

Asda Mobile

Asda Mobile launched unlimited data plans later than most, but they’re available now, alongside 5G speeds using Vodafone’s infrastructure.

At the time of writing the network sells three different unlimited data 30-day SIM Only plans, and while they all let you use 5G signals, only the one listed at ‘150Mbps’ will offer 5G speeds – the other two options are slower, and even the top option is presumably capped, since 5G is capable of higher speeds than 150Mbps. Asda Mobile also allows tethering and free roaming (sometimes at 5G speeds) in much of Europe (up to a 5GB limit), but there aren’t any handset plans – you can only go SIM Only or pay as you go, or spread the cost of a phone that you buy outright.

Related reading: Asda Mobile Review and Coverage

Giffgaff

Giffgaff, which use O2's network, offers an unlimited data SIM Only plan on a 1-month or 18-month contract, as well as a 100GB Always On 1-month plan, which also has unlimited data included. These plans can alternatively be purchased with a mobile phone, and they include 5G.

There are some restrictions with the 100GB Always On plan though, with only the first 100GB of use per month being at full speeds. After that, speeds are capped at 384kbps between 8am and midnight, which is quite slow. You can tether, but the same speed restrictions apply.

The unlimited data plans have no such speed restrictions, but it costs more if you take the 1-month rolling option, and there is a fair usage policy stating that you should use under 650GB of data a month, and shouldn’t tether with 12 or more devices at once.

Free roaming meanwhile is fully capped at 5GB per month on both plans and the only way to use your data beyond Europe is to pay for the roaming data separately.

Related reading: GiffGaff Review and Coverage

Honest Mobile

Honest Mobile uses Three’s network for its coverage, and it sells an unlimited data SIM Only plan that you can get in either a 30-day or 12-month duration.

This includes 5G plus unlimited minutes and texts, and while its standard pricing is fairly average, the network rewards loyalty by decreasing the price over time. Honest Mobile’s other main selling point is being carbon negative, so it’s good for the planet.

It also lets you roam in the EU at no extra cost (though you only get five free roaming days per trip and there’s a 20GB fair usage limit).

When using your phone in the UK, Honest Mobile’s only fair usage restriction is that your speeds might be limited to 3G if you use more than 650GB of data in a single month.

Related reading: Honest Mobile Review and Coverage

iD Mobile

iD Mobile, which uses the Three network and is owned by Currys plc, offers an unlimited data plan on a 1, 12 or 24-month SIM Only contract, or as part of a 24-month handset plan.

Roaming abroad in 50 mostly European destinations is included (up to a 30GB fair usage limit) and you can also tether as much data as you like. When roaming there’s also a fair usage policy which states that if you spend more time abroad in a 4-month period than in the UK you may be asked to prove you have strong ties to the UK.

Like Three's unlimited plans, iD Mobile's unlimited plans are 5G ready, so you will be able to enjoy 5G speeds. At the current time iD Mobile does not specify a fair usage policy with regards to data usage in the UK.

Related reading: iD Mobile Review and Coverage

Lebara Mobile

Lebara (which runs off Vodafone’s infrastructure) offers 30-day and 12-month SIM plans that come with unlimited 5G data, minutes, and texts.

The network additionally lets you roam for free across the EU and India, and use your data to tether, but the big selling point is you also get either 100 or unlimited minutes of international calling to either 41 or 42 countries, including Australia, United States, Canada, India, New Zealand, China and many more locations.

There aren’t any fair usage restrictions in the UK, but when roaming you’re limited to 30GB of data.

Related reading: Lebara Mobile Review and Coverage

Lyca Mobile

Lyca Mobile, which uses EE's network, has launched unlimited data plans, and these also give you unlimited minutes and texts.

Some of these plans give you unlimited data at 5G speeds plus 100 international minutes to dozens of locations, while one does the same but with unlimited international minutes. You can tether on Lyca Mobile too, and you can roam within the EU and India at no extra cost – though there’s a 30GB or 35GB cap (depending on plan) when doing that.

There’s also a general fair usage policy saying you should limit your use to under 450GB per month.

Related reading: Lycamobile Review and Coverage

Smarty

Smarty, which uses Three's network, offers a great value unlimited data SIM plan which comes with no speed or tethering restrictions. 

Smarty's unlimited plan is a 1-month rolling plan that comes with 5G included.

Currently, Smarty only offers SIM only plans, so no unlimited Pay Monthly phones or Mobile Broadband plans are available.

Data roaming is limited to 12GB per month, and you can only roam for free across the EU, which is another key difference with Three's plans, as these include roaming in a number of places further afield too – although it typically comes at a small cost.

Related Reading: Smarty Mobile Review and Coverage

Spusu

Spusu uses EE’s network, so its coverage and speeds are strong, and its unlimited data SIM Only plan is on a flexible 30-day rolling contract, but comes with the promise of a price freeze until 2026.

Spusu’s plans also all come with 500 international minutes, which you can use to call the EU, and you can roam for free in the EU as well (up to a fair usage limit of 15GB).

In the UK though, Spusu has no fair usage restrictions, aside from saying its SIM cards shouldn’t be used commercially or as a long-term alternative to home broadband.

Related reading: Spusu Review and Coverage

Talkmobile

Talkmobile is owned and operated by Vodafone, so it has the same coverage, but its prices are lower.

It offers 5G unlimited data SIM Only plans in both 1-month and 12-month durations, and you can roam across the EU at no extra cost (up to a 5GB fair usage limit).

Talkmobile also allows tethering, and doesn’t appear to have any real fair use limits in the UK.

Related reading: Talkmobile Review and Coverage

Tesco Mobile

Tesco Mobile, which uses O2's network, offers unlimited data on both SIM Only and Pay Monthly, and it supports 5G.

The plans are available in 1, 12 or 24-month varieties on SIM Only, or variable lengths with a handset. You can also roam for free in Europe (at least until 2025) and tether.

There’s no fair usage limit in the UK, other than that it should be for your personal use and on your own mobile, and there isn’t really when roaming either – except that you should be using your phone more in the UK than abroad.

Related reading: Tesco Mobile Review and Coverage

VOXI

VOXI, which is a network run and owned by Vodafone, is now offering a 5G 30-day unlimited data plan.

Importantly, VOXI's unlimited data plan comes with 5G as standard and has no speed restrictions. Tethering is also included so you can share data over a personal hotspot, and you also get cheap – but not free - roaming in Europe (up to 20GB per month).

Overall, VOXI's unlimited data plan is a more affordable alternative to the equivalent plan on Vodafone, though Vodafone gives you more options in terms of duration and speed.

Related reading: VOXI Network and Coverage Review

Is unlimited data really unlimited?

In most cases when using your phone in the UK unlimited data really is unlimited. However, some networks limit speeds on certain plans. It's also worth noting that the majority of networks have usage limits when roaming abroad with an unlimited data plan. 

These details were up to date to the best of our knowledge at the time of writing, but it’s always worth checking with a network directly if in doubt. Also note that where there are no fair usage restrictions listed, it’s still likely that the network doesn’t allow commercial use.

Speed restrictions

At the time of writing, all networks with unlimited data plans offer 5G, so you can potentially get the maximum available speeds in the UK.

In a lot of cases, the only limit will be your phone, your network’s infrastructure, and the coverage in your area. However, some plans on some networks do have additional limits.

Specifically, standard Unlimited plans on Vodafone top out at 10Mbps. So for unrestricted speeds you need an Unlimited Max plan.

Similarly, Asda Mobile caps its unlimited data plan speeds at either 2Mbps, 10Mbps, or 150Mbps – the last of those won’t slow you down much, but it’s still a limitation.

Fair usage policies

Outside of tethering and roaming, which we’ll touch on below, no UK networks have significant fair usage restrictions.

Most networks do have a fair usage policy, but they are typically only in place to identify commercial or illegal usage. Therefore, those using the plans for personal usage don't need to worry about them.

However, O2 and Giffgaff ask you to keep your usage under 650GB per month, while EE wants you to keep it under 600GB, and Lyca Mobile states under 450GB. Those limits are high enough that they should hardly affect anyone though.

Tethering restrictions

When tethering, few networks mention any limits, but O2, EE, and Giffgaff say you shouldn’t tether your phone to more than 11 other devices at a time. And of course where networks have fair usage data limits (detailed above) they will apply to tethering too.

Roaming abroad

The main limits with unlimited data plans come when roaming, as almost all networks apply a cap to the amount of data you can use from your allowance when abroad.

This cap varies a lot, from 5GB on Asda Mobile, Giffgaff, and Talkmobile, to 50GB on EE, but in all cases – other than with Tesco Mobile, which doesn’t mention specific limits – it’s a lot less than unlimited.

Can I get unlimited data on Pay As You Go?

Pay As You Go plans with unlimited data are currently available on iD Mobile, Giffgaff, Lyca Mobile, Three and Vodafone. They offer even more flexibility and don't require a credit check, but you will have to pay a little more than a pay monthly plan.