Unlimited data SIM-only deals

Unlimited data SIM icon

Always using your smartphone? Like to stream music on the go, watch iPlayer on the train, and download lots of apps? You're best off with an unlimited data SIM deal.

This week's best unlimited data SIM deals

Provider Data Amount Contract Length Monthly Costs
GiffGaff sim only Unlimited data 1 month £25.00 p/m
SMARTY sim only Unlimited data 1 month £18.75 p/m
O2 sim only 50GB data 12 months £45.00 p/m
  • GiffGaff sim only
    4G
    • Unlimited 4G data
    • Unlimited minutes
    • Unlimited texts
    • Speed restrictions apply after 40GB of data use
    • £25.00 per month
    1 month contract From giffgaff
  • SMARTY sim only
    4G
    • Unlimited 4G data
    • Unlimited minutes
    • Unlimited texts
    • 25% off normal price
    • £18.75 per month
    1 month contract From SMARTY
  • O2 sim only
    4G
    • 50GB of 4G data
    • Unlimited minutes
    • Unlimited texts
    • £45.00 per month
    12 month contract From O2

Unlimited data SIMs mean no more worrying about running up high bills for exceeding your usage limit. And, of course, no more worrying about running out of data either.

You'll find our pick of the best unlimited data SIM only contracts in the table above.

All of which have been handpicked by our experts, taking into account price, coverage, speeds, reward schemes and more.

Best unlimited SIM only deals on Vodafone

All Vodafone unlimited-data SIMs include a three-month trial of SecureNet. Depending on the plan you choose, you'll be able to use your UK allowances in 48 or 77 destinations overseas for no extra charge.

And on select unlimited plans, you'll be able to choose from a free, 12-month subscription to Now TV, Sky Sports Mobile, Amazon Prime Video or Spotify.

Best unlimited SIM only deals on O2

O2 doesn't offer unlimited data SIMS. The closest is a 50GB monthly allowance, which should still be plenty for all but the heaviest users.

O2 SIMs with unlimited data include daily offers with its Priority customer rewards app, as well as free O2 WiFi.

Best unlimited SIM only deals on Three

Provider Data Amount Contract Length Monthly Costs
Three sim only 100GB data 12 months £18.00 p/m
Three sim only Unlimited data 12 months £21.00 p/m
  • Three sim only
    4G
    • 100GB of 4G data
    • Unlimited minutes
    • Unlimited texts
    • £18.00 per month
    12 month contract From Three Mobile
  • Three sim only
    4G
    • Unlimited 4G data
    • Unlimited minutes
    • Unlimited texts
    • £21.00 per month
    12 month contract From Three Mobile

Three unlimited SIMs stand out for being well priced and are available as one-month, rolling contracts or 12-month contracts.

Depending on whether you choose an Essential or Advanced plan, you'll get inclusive roaming in 48 or 77 locations.

All Three unlimited data plans offer freebies and money-off promotions with the Wuntu rewards app.

Best unlimited data SIM only deals on EE

EE doesn't offer SIMs with unlimited data. But you can get high data usage plans, which also get you its fastest 4G speeds.

Smart Plans include benefits you can swap from month to month, such as BT Sport and passes that allow you use streaming services or social media sites without eating into your data allowance.

It's also worth noting that EE is consistently named the UK's best network for mobile internet coverage and speeds.

Best unlimited data SIMs on Smarty

Get an unlimited data deal on Smarty and you'll be able to use your UK allowances in the EU, for no extra charge.

Smarty SIMs also allow you to tether, so you'll be able to use your plan to get online with other internet-enabled devices, such as a laptop or tablet.

One caveat to be aware of: unlike most of its plans, Smarty unlimited data plans don't offer money back for any data left unused at the end of the month.

How to find an unlimited data SIM

It's easy... Just use a mobile SIM comparison tool like ours:

  • Adjust the filters at the side to include just those deals with unlimited data, or at least a nice high data allowance
  • You can filter for other things too, such as minutes and texts allowances, networks, and budget.
  • If you're only interested in unlimited data plans, bear in mind that your options are (ironically enough) a little more limited.

Can I get a mobile contract with unlimited data?

Yep - there are plenty of contracts on handsets that include unlimited data too.

  • They're offered by the same networks as above, so once again your options are a little limited, but landing a deal is totally possible.
  • You'll find unlimited data plans on a huge variety of handsets, including big ones like the iPhone XS and Samsung Galaxy S9 Plus, and more budget-friendly smartphones too.
  • It's also worth noting that many networks offer higher data allowances on phone contracts than they do on their SIM-only plans. If you can settle for, say, 20GB or 30GB of monthly data, your options for a contract plan open right up. It's worth considering if you fancy a new phone.

Pay-as-you-go SIM-only deals

If a long-term mobile contract doesn't appeal, you can always go for a Pay As You Go (PAYG) SIM deal - a great option if you want to keep your old handset.