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Best high data and unlimited data Sim-only deals

Need a Sim with lots of data as a backup for shoddy broadband? We round up all the cheapest deals

Best high data and unlimited data Sim-only deals

If you find you’re using more data than normal and there’s a risk of blowing through your bundle, you might want to consider upping your allowance to avoid a huge bill.

Getting a high data Sim deal (for example, 20GB of data and above) is not as expensive as it used to be, with many new low cost ‘virtual network’ providers, which use the network of the main four mobile providers (EE, O2, Three and Vodafone) offering ultra-cheap deals.

So if you are in the market for a cheap Sim-only deal with lots of data for whatever reason, our round-up has you covered.


Data’s not everything. Read how real customers rated the best and worst mobile networks for 2020.


Cheapest high data Sim-only deals

The market has seen lots of great deals recently and the table below highlights the costs from each of the main providers.

Provider Data Minutes Contract Cost (per month)
Virgin Mobile 24GB Unlimited 12 Months £12
iD Mobile 20GB Unlimited 1 Month £14
Tesco Mobile 25GB 3,000 12 Months £15
iD Mobile 50GB Unlimited 1 Month £16
Three 100GB Unlimited 24 Months £18
Virgin Mobile 50GB 5,000 12 Months £19
GiffGaff 80GB Unlimited 1 month £20
O2 50GB Unlimited 18 Months £20
EE 60GB Unlimited 18 Months £20
Vodafone 20GB Unlimited 24 Months £27
* prices correct as of 26 March 2020

High data Sim deals are currently going for as little as £12 per month, with Virgin Mobile also giving customers 10GB extra data on top of the allowance above and unlimited minutes for one month due to the coronavirus.

If you’re not keen on tying yourself down for 12, 18 or 24 months, many providers do offer monthly deals too, but these are often quite a bit more expensive. For example, O2 has a 30-day contract with 50GB of data for £37 per month – almost double the cost of the same data allowance on an 18-month contract.

However, If you are looking for a short contract on the cheap, iD Mobile and GiffGaff have some great deals currently, and all include unlimited minutes and texts. iD Mobile’s signal is carried by Three, whereas GiffGaff’s signal is carried by O2, so make sure to check that the signal for those providers is good where you live.

Find out what the signal is like where you live with our coverage map.


Having broadband problems? We have plenty of help and advice in our guide on how to boost and fix broadband in the home.


Cheapest unlimited data Sim-only deals

If you’re after a deal with unlimited data, there’s plenty to choose from on this front, too.

Provider Data Minutes Contract Cost (per month)
Three Unlimited Unlimited 24 months £19.25*
iD Mobile Unlimited Unlimited 1 month £21
GiffGaff Unlimited Unlimited 1 month £25
Vodafone Unlimited Unlimited 24 Months £26.25*
O2 Unlimited Unlimited 18 Months £33
EE Unlimited Unlimited 12 Months £34

* Three and Vodafone prices incorporate both the standard price and the intro price for the first six months.

Although Three’s deal is cheaper, the long contract coupled with multiple inflation-linked price rises means that GiffGaff and iD Mobile are better options for those looking for a short-term solution.

How to switch to a high-data deal

If you’ve found some deals you like the look of from the tables above, you might also be wondering about the best way to take advantage of this extra data.

Your options likely depend on your situation – particularly if you’re still in contract with a lower data bundle. If you are, your best bet is to try and get a bigger data deal with your current provider, otherwise you may have to ‘buy yourself out’ of your current contract, which could prove costly. If you’re out of contract, or paying Sim-only prices with a provider like GiffGaff, it’s easy to up the allowance, or you could switch to a different provider.

Get a bigger data deal with your current provider

Depending on who your current provider is, you may be able to change your current package to one that allows you to use more data. This will be much easier for those on a 1-month contract as the contract can be changed before the next billing date to take effect after.

With longer contracts, it may require you to speak directly with the provider and may be at their discretion, depending on what deals the provider has available.

How to switch to a Sim-only deal with a new provider

If you’re out of contract, it’s far easier. This is another benefit to opting for 1-month contracts, over 12 or 24-month.

In this case, if you’re otherwise happy with your current provider, simply upgrade your monthly bundle to a higher-data deal. Or, you could switch. Switching has never been easier, and just by texting PAC to 65075, you can get your switch code  (also known as a PAC – Porting Authorisation Code) and keep your number without even having to speak to a customer service agent.

How to use your phone as a wi-fi hotspot

One of the benefits of having a higher data deal is that you can use your phone as a wi-fi hotspot without worrying about using up your allowance. This can be useful if you’re having broadband issues, since you can connect other devices like laptops and tablets to the internet through your mobile phone.

Nowadays, most providers allow you to tether your phone, but some may have limitations on the amount you can tether (eg you may have a 50GB data limit but 25GB tethering limit) so check the terms and conditions for the plan.

Read our guide to setting up a mobile phone wi-fi hotspot for more.

You can keep up to date on our latest coverage over on our coronavirus advice hub.

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