giffgaff vs O2: the main differences between the networks

✔ Same 4G, 5G and call signal on both networks

giffgaff are a budget provider that use O2’s network for signal and are actually owned by O2. You might think that joining a smaller, cheaper provider will give you a worse experience, but is that actually the case?

Our own tests have always found coverage the same between giffgaff and O2. Although you can end up on different mast bands on both. We’ve never found the intrinsic signal worse or better on either though.

Compare O2 and giffgaff’s best SIM only deals

That’s good because O2 are still leaders in signal for calls and texts around the UK. Their 4G data signal is massive too, though has now slipped behind EE and Three a little generally.

giffgaff also offer 5G in the same list of 3200+ towns and cities to O2. Coverage varies by street, but O2 have a good track record for covering their declared locations. We’d argue they have the furthest reaching 5G signal of any network.

Useful link: How good is O2’s indoor coverage?

✔ Data speeds aren’t capped on giffgaff vs O2

Some giffgaff users have reported they’ve found their SIM slower than O2. We think this effect is more likely in busier, more congested places. And we've never managed to observe this ourselves in our own tests.

We've hit 95 Mbps on both over 4G, while speeds went down to 5 Mbps in the countryside. Most often we sat in the mid 20 Mbps range on both. That lines up nicely with Opensignal's typical 4G speed result of 23.1 Mbps, the slowest among the big networks. That’s still enough for smooth browsing and HD streaming.

5G speeds are also shared. Opensignal and Speedtest show sluggish typical results of 80.1 Mbps and 83.02 Mbps with peaks of 226.14 Mbps. This puts O2/giffgaff in last place, but still fast enough for most users.

Best 5G SIM only plans on these networks

If you want the highest speeds possible, giffgaff and O2 won’t be your top pick. But for most users, the performance is good enough across 4G and 5G. And there’s no difference between them for speeds.

Useful link: Read giffgaff’s guide to 5G

✔ O2 have better WiFi calling and more network features

Both networks now offer WiFi/4G calling to help you stay connected indoors where call signal might struggle. But giffgaff support a smaller list of devices, and in our tests it didn’t work on our older test phones.

O2’s scheme works on a much wider range of devices and lets calls move from WiFi to 4G signal without dropping. It’s also available on most pay monthly plans, but it won’t work on their PAYG plans.

See our exclusive O2 deals

And O2 offer around 15,000+ WiFi hotspots including on the Underground, with roughly 8000 that connect automatically. giffgaff users get access to around 7000 of these, but it’s harder to set up.

giffgaff now offer eSIMs and call forwarding which very few smaller networks do. The only other feature they miss out that O2 have is visual voicemail. O2 do have better features, but it’s closer than you might think.

Useful link: The best UK networks for WiFi calling

✔ O2 have better roaming than giffgaff in the EU and beyond

Both O2 and giffgaff include EU roaming on all plans. But O2 offer more flexibility, letting you use your mins, texts and up to 25GB in these 49 EU countries. If your data amount is smaller, you can use it all.

giffgaff’s EU roaming is now much more restrictive. You’re limited to just 5GB of your allowance in these 37 EU countries. After that, you’ll need to pay extra to keep using data, which can add up quickly.

Best current EU roaming deals on O2 and giffgaff

You can get O2’s Travel Inclusive Zone as an extra on premium plans. This lets you roam in 27 worldwide countries with 120 mins, 120 texts and 150MB of full-speed data. After that, data is unlimited but very slow.

giffgaff don’t offer any inclusive worldwide roaming at all. You’ll have to top up and pay high rates if you want to use your phone outside the EU. So O2 are the better choice for the EU and beyond.

Useful link: O2’s full roaming terms

✔ O2 offer a lot of extras to make their plans better value

O2 offer a lot to make up for their high prices. O2 include one free trial to Disney+, Amazon Prime Video, Audible or Music Unlimited of your choice. Trials range from 1 to 6 months depending on your plan’s price.

And every O2 user gets access to O2’s rewards app called Priority. This gives you discounts on high-street food, drinks and shopping, as well as some genuine freebies from time to time.

Best SIM only deals currently on O2

On top of that you can get presale ticket access to gigs and sports events at O2 venues and VIP treatment at some events. All of this combined is why O2 have the best rewards app of any network in our eyes.

Lastly, O2 give you 20% off any additional SIM only plans or the usage plan of any phone deal you add to your existing account. Up to 20 plans can be linked, which makes it one of the more generous multisave schemes available.

Useful link: See all of O2’s Extras and which plans include them

✔ giffgaff have great flexibility and refer-a-friend rewards

giffgaff’s 1-month plans work more like PAYG than a contract. You choose a monthly bundle of mins, texts and data but you’re never tied in. There’s no credit checks and you can leave or change your plan whenever.

They're ideal if you’ve been rejected for a contract elsewhere or want the freedom to change your plan. O2’s SIM only and phone plans are fixed for 12, 24 or 36 months, with no plan changes allowed during the term.

giffgaff do also have some 18-month SIM only contracts which are better value per month than their 1-month plans. And these still let you change plans each month and join without credit checks.

Best current SIM only plans on giffgaff

And giffgaff reward you for getting others to join. Their Payback scheme gives you £5 for each friend you refer. Your friend also gets £5 free credit after getting a £10 goodybag or higher, so you both benefit.

Useful links: giffgaff’s Payback and referral scheme

✔ O2 offer great flexibility on their phone contracts

O2 offer most phones on their “Refresh” contracts. These split your bill into two parts: one for the repayment of your phone and one for your usage (mins, texts, data). Both are rolled into a single monthly payment.

As you’re basically taking a loan for your phone, you can pay off the cost of your phone at once whenever. That lets you upgrade earlier than usual. You can also change your usage plan each month if you need to.

Their Custom Plans let you adjust the upfront cost and choose a contract length between 3 and 36 months. This controls how much you’ll pay monthly and spreads the cost in a way that suits you.

No matter what options you pick, the total price of the phone stays the same. It’s a very flexible setup. Just note that passing a credit check might be tougher than on other networks.

Useful link: How to set your O2 phone contract how you like it

✔ giffgaff also offer great flexibility and lower prices

giffgaff sell phones through finance agreements. You pay one part for your phone and the other part for your usage plan that makes up your monthly bill. This setup gives you flexibility each month.

You can still change your plan up or down or leave giffgaff completely while continuing to pay off your phone. There’s also the option to pay lump sums to reduce your bill or upgrade early.

Like O2, giffgaff let you set your upfront payment and pick a contract length that suits you. However, the flexibility isn’t quite as advanced as O2’s due to having fewer contract lengths to choose from.

That said, giffgaff are usually cheaper than O2 for phone contracts. So you’re trading some flexibility for better value. Which network you prefer depends on what matters most to you.

Useful link: giffgaff’s full range of phone contracts