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Are giffgaff’s 18-month SIM-only plans worth it?

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giffgaff has launched a new range of 18-month SIM-only plans – and just like everything giffgaff, they operate a little differently. So are they worth getting?

What are giffgaff 18-month SIM deals?

An 18-month SIM from giffgaff is exactly what it sounds like: a SIM-only deal for your mobile phone, which contracts you in for 18 months.

But unlike most long-term SIM plans from other networks, giffgaff’s come with one key difference. You can change your allowance – and therefore the price of your bill – every single month.

That means you get much of the flexibility of a rolling, 30-day SIM, but with the lower prices of a long-term deal. As a nice bonus, giffgaff has also fixed all its pay-monthly prices until the end of 2023.

Another bonus is that giffgaff doesn’t perform credit checks on its 18-month SIMs. So it’s a great way to get your hands on a good-value, long-term deal even if you’ve got a poor credit history.

As for the technical details, giffgaff uses O2’s network to deliver its services, so coverage is excellent. You’ll also get 5G included as standard – perfect if you have a 5G-ready handset and frequent 5G-covered areas.

How do giffgaff’s 18-month SIMs work?

  1. Compare giffgaff SIM-only deals, and pick a data allowance that suits you. Click through to sign up on the giffgaff website. Since there are no credit checks, it’s ultra-quick and easy
  2. When your SIM arrives, put it in your phone and activate it. You’re now good to go for 18 months
  3. If you want to change your allowance at any point – whether to upgrade or downgrade – just log on to your account on the giffgaff website or app

And that’s it. All you get is a straightforward, quality SIM. giffgaff may be a bit lacking in perks – there’s no O2 Priority, for instance, despite using the same network – but that means it can afford to give you better prices in the first place.

When the 18-month period is up, you can change to a rolling 30-day SIM, sign up long-term all over again, or switch to a different network without penalty.

Can I get unlimited data?

Yes you can, but choose wisely.

giffgaff has two plans with data that never runs out: unlimited data, or ‘Always On’ data.

The standard unlimited data plan works just like any other. You can use as much data as you like, for a set price, with no limitations. All you’re subject to is a fair usage policy, but you’d need to be using an extremely high amount of data before you breach it. (The official policy gives a figure of 650GB twice in a six-month period.)

Always On data, meanwhile, works slightly differently. It’s cheaper, but has limits. You can use up to 120GB of data per month at the fastest speeds available… but after that point, your download speed is throttled to a sluggish 384kbs between 8am and midnight for the rest of the month.

It can be a great way to save money if you want unlimited data but aren’t likely to exceed 150GB per month – or if you work the night shift. But if you’re a heavy mobile user, you may prefer the standard Unlimited plan.

On the plus side, if you try one and find it isn’t for you, you can switch it out next month.

What are the pros and cons?


  • More flexible than other long-term SIM plans
  • Great value
  • All plans include 5G as standard
  • Broad range of allowances to choose from
  • Uses O2’s network, so coverage is great
  • No credit check necessary
  • Start the next month early if you run out of data
  • Lower termination charges than some providers’


  • Longer commitment than some long-term SIM contracts, which are often 12 months
  • Less flexible than one-month plans, which you can cancel at any time
  • Roaming isn’t great, and capped at 5GB per month in the EU
  • ‘Always on’ plan has drawbacks – see above

So are they worth it?

If you’re looking for a SIM-only deal to put in your phone, and are happy to sign up to a long-term plan, giffgaff’s 18-month plans are a great choice. They’re good value, and the flexibility they offer is a huge, huge boon for this kind of commitment.

There are a few downsides – you may be better served elsewhere if you often roam internationally, for instance – but giffgaff is absolutely worth considering.

For a full look at the SIM plans available, compare SIMs with MoneySuperMarket to find the latest deals that tick every box.

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