Best giffgaff SIM deals: 25GB for £10, 100GB for £15

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See how giffgaff compare on price this month vs the competition on SIM only. We've checked each of their plans to find the best. Last updated: 13th June 2025.
giffgaff's best SIM only deals
The best overall SIM only deal this month on giffgaff

just
£10
a month
✔ Unlimited mins and 25GB data See full deal
at giffgaff.com
(opens in new window)
Out of all the SIM only plans available this June on giffgaff, we'd say their best value deal is their 18‑month SIM below, which gets you 25GB data, plus unlimited minutes and texts for £10 a month:

Unlimited minutes + Unlimited texts +
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It might not be the lowest-cost SIM only deal with 25GB data or more on the entire market but if you're sure you need a SIM using the O2 network, it is the best-priced. Here's where you can beat it on other networks:

Unlimited minutes + Unlimited texts + 20GB 40GB data (5G) = £6.95 a month (1‑month contract)
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Unlimited minutes + Unlimited texts +
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Unlimited minutes + Unlimited texts +
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Unlimited minutes + Unlimited texts + 40GB 80GB data (5G) = £10 £8 a month for 15 months, then £10 (1‑month plan, no contract)
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Unlimited minutes + Unlimited texts + 25GB 80GB data (5G) = £16 £8 a month (12‑month contract)
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Unlimited minutes + Unlimited texts +
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Unlimited minutes + Unlimited texts +
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Unlimited minutes + Unlimited texts +
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Unlimited minutes + Unlimited texts +
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Their 100GB for £15 SIM is another good option

just
£15
a month
✔ Unlimited mins and 100GB data See full deal
at giffgaff.com
(opens in new window)
To get more data, giffgaff are also offering this £15 SIM, which includes 100GB data, unlimited minutes and texts on a 18‑month plan. It's another of their best deals:

Unlimited minutes + Unlimited texts + 40GB 100GB data (5G) = £15 a month (18‑month contract)
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If you don't need your SIM to be on a provider that uses the O2 network, you can beat this deal elsewhere. But if you do, it's the cheapest 100GB data or more option. See lower-priced networks' deals here:

Unlimited minutes + Unlimited texts +
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Unlimited minutes + Unlimited texts + £11.95 £9.95 a month (1‑month contract)
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Unlimited minutes + Unlimited texts + 70GB 100GB data (5G) = £10 a month (24‑month contract)
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Unlimited minutes + Unlimited texts +
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Unlimited minutes + Unlimited texts +
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Unlimited minutes + Unlimited texts + £22 £12 a month (12‑month contract)
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giffgaff's 200GB for £20 plan is a good option too

just
£20
a month
✔ Unlimited mins and 200GB data See full deal
at giffgaff.com
(opens in new window)
For people who need even more data, you might like the £20 SIM only deal running on giffgaff at the moment. It's a 18‑month plan, which comes with 200GB data, unlimited minutes and texts too:

Unlimited minutes + Unlimited texts + 120GB 200GB data (5G) = £20 a month (18‑month contract)
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It isn't actually the cheapest 200GB data or more SIM available overall this month but if you definitely need your plan to use the O2 network, it is the lowest cost option. Here are other networks you can beat it on:

Unlimited minutes + Unlimited texts + £22 £12 a month (12‑month contract)
See full deal

Unlimited minutes + Unlimited texts + 100GB 200GB data (5G) = £12 a month (1‑month plan, no contract)
See full deal

Unlimited minutes + Unlimited texts +
See full deal

Unlimited minutes + Unlimited texts +
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Increased to: £18.60 on April 1 2027

Unlimited minutes + Unlimited texts +
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Unlimited minutes + Unlimited texts + £18 £9 a month for 6 months, then £18 (24‑month contract)
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Unlimited minutes + Unlimited texts +
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Unlimited minutes + Unlimited texts + 100GB 300GB data (5G) = £20 a month (1‑month plan, no contract)
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How giffgaff's deals compare with other networks

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More about giffgaff's SIM only plans
How giffgaff’s benefits and SIM only prices stack up
In our full review of giffgaff we said we like that they offer full access to O2’s 5G/4G/3G/2G network at much lower costs than joining O2 directly. They also have a nice free WiFi hotspot scheme on top of that.
giffgaff market their SIM only deals (their “goodybags”) as monthly bundles of minutes, texts and data with no contracts. Compare their plans here to find the best possible deal.
Their best value plans are their mid-range data deals. For these they work out as one of the cheapest providers on the O2 network.
giffgaff still offer inclusive EU roaming on all plans at no extra cost. And you can get £5 free credit on your first £10 top up or bring a friend onto giffgaff to both get £5 free credit.
Useful link: Read our full giffgaff review
What else you should know about giffgaff’s SIM only plans
You’ll receive your SIM package within 2 working days. And you can even have it delivered in the EU within 3-5 days and beyond the EU around 5+ days after you order. giffgaff don’t offer eSIMs (these networks do).
If you’re not happy with your SIM you can return it to get a refund within 14 days. But you only get a refund on what you haven’t used, so you won’t get a full refund if you used some data (read more here).
Since you’re paying for your minutes, texts and data up front then you won’t have to pass a credit check for their SIM only plans. You’ll just have to give them some details so they know who you are.
If you want to switch to giffgaff from another network while keeping your old number you’ll have to request a PAC from your old provider to give to giffgaff. You can read their instructions on how this works here.
Useful link: Compare all giffgaff SIMs