giffgaff vs SMARTY: how the budget SIMs differ

giffgaff and SMARTY both sell low-cost SIM only plans, and each is a smaller brand owned by one of the big network groups. giffgaff is owned by Virgin Media O2 and runs on O2's masts. SMARTY is owned by VodafoneThree and runs on Three's network. That network split matters more than any price difference, because it decides the signal you get at home. After that, it comes down to contracts, price-rise promises, roaming and extras.

How do giffgaff and SMARTY compare at a glance?

The table pulls prices and price rises from our live deal feed, so it matches the deals on our comparison pages today. The roaming, eSIM and exit-fee rows come from each network's own pages.

Which has better coverage where you live?

That depends on your area, because they use different masts. giffgaff uses O2. SMARTY uses Three, and since the Vodafone and Three merger it can also use Vodafone masts where the two networks share sites. Vodafone says that sharing had been switched on at 10,000 mast sites by April 2026, and names SMARTY among the brands that benefit.

Nationally, Ofcom's January 2026 figures put the two host networks close together. Three's 4G reached 96.6% of premises indoors against O2's 95.5%, and 85.0% against 82.0% indoors in rural areas. O2 was ahead on outdoor 5G, at 86.2% of premises against Three's 75.9%.

National averages hide big local gaps, so check your postcode on our mobile coverage map before anything else. If one network is clearly weaker at your home or work, that settles it.

Which is cheaper, giffgaff or SMARTY?

Both start at the same price, but not with the same data. When we checked on 23 September 2026, each network's cheapest plan in our feed cost £6 a month. SMARTY's came with 18GB of data and giffgaff's with 2GB. For unlimited data, SMARTY charged £17 a month on a rolling plan. giffgaff charged £20 on a rolling plan, or £14 on an 18-month contract.

Both networks were running time-limited bonus data when we checked. giffgaff was adding extra gigabytes to its 18-month plans, and SMARTY was doubling the data on some of its plans. Offers like these come and go, so compare the plan you'd keep once the bonus ends. Our data allowance guide helps you work out that figure.

Do you have to sign a contract?

SMARTY doesn't use contracts at all. Every plan is 30-day rolling, and SMARTY's own summary is "Cancel or change plans anytime. No contracts, no credit checks and no surprises at the end of the month".

giffgaff offers a choice. Its monthly rolling plans work the same way as SMARTY's. Its 18-month contracts cost less, and giffgaff says "Contracts are our best value plans". You can change between plans each month without restarting the term. Leaving early costs half the monthly price for each month left, so a £14 plan with ten months to go would cost £70 to end.

If you want the lowest monthly price and expect to stay, giffgaff's contract delivers it. If you want to be free to leave at any point, SMARTY and giffgaff's rolling plans both allow that.

Can the price go up?

Neither has a scheduled rise in our feed. SMARTY says: "We don't do annual price rises with our rolling one month plans". giffgaff's deals page promises a "Price lock" with "no mid-contract price rises" on its 18-month contracts, though its general terms keep the right to change prices with advance notice.

On a rolling plan, any rise would come with notice and you could simply leave. That's the practical safety net on both. Our price rise guide covers the rules if a network does change its prices.

Will either run a credit check?

Neither does for SIM plans. SMARTY says: "Because our SMARTY SIM-only deals are paid up-front on a rolling monthly plan, we do not require you to have a credit check". giffgaff says: "They'll only carry out a credit check if you buy a phone on a contract with a loan". That covers its 18-month SIM contracts too.

Which is better for roaming and extras?

For EU trips, SMARTY lets you use up to 12GB of your monthly allowance, with unlimited UK and EU calls and texts. giffgaff includes up to 5GB, then charges 10p for each extra MB, according to its plan pages. If you use a lot of data abroad, SMARTY's allowance goes further. Our EU roaming guide covers the details.

For families, SMARTY runs Group plans: bring 2 to 8 plans together and save 10% on each. giffgaff's plan pages don't offer a multi-SIM discount. SMARTY also says you can "tether and hot-spot all of your data with no speed caps" in the UK.

For rewards, giffgaff has Payback. Members earn points for recommending friends, answering community questions and suggesting ideas, paid out twice a year as PayPal cash, credit or a charity donation. SMARTY offers referral gift cards of up to £20, according to its plan pages.

How does customer service compare?

Neither has a phone line. giffgaff offers an online help hub, an AI assistant that passes you to human agents, and a member community forum. SMARTY offers a 24/7 chatbot, human chat from 8am to 8pm, email and a community forum.

Ofcom publishes figures for giffgaff but not for SMARTY, which falls below the market-share threshold Ofcom uses in its reports. giffgaff recorded 1 complaint per 100,000 customers from January to March 2026, against an industry average of 2. In Ofcom's 2024 survey, 94% of giffgaff customers were satisfied overall, against an 88% average. There's no like-for-like Ofcom figure for SMARTY, so we don't substitute one.

Why you might choose giffgaff

• O2's signal is stronger where you live, work or travel.
• You want the lowest price on unlimited data and can commit for 18 months.
• You'd use Payback, or you like the member community model.
• You want a network whose service Ofcom measures and publishes.

Why you might choose SMARTY

• Three's signal, plus shared Vodafone masts, is stronger in your area.
• You never want a contract, and prefer to stay rolling.
• You'd bring several SIMs into a Group for 10% off each.
• You use more than 5GB of data on EU trips.

How do you switch between giffgaff and SMARTY?

This switch changes your network, so check coverage first. To keep your number, text PAC to 65075 from your current phone. The code arrives within a minute, and your new network completes the switch within one working day under Ofcom's rules. Our switching guide covers each step.

Leaving SMARTY costs nothing, since its plans roll monthly. Leaving a giffgaff 18-month plan early costs half the monthly price for each month left. Our guide to leaving early sets out every network's rules.

Sources and how we checked

Prices, contract lengths and scheduled rises come from our live deal feed and refresh whenever the site updates. We checked giffgaff's SIM deals page, terms and credit check help, and SMARTY's plan pages, Group plans, roaming page and credit check page, on 23 September 2026. Network sharing figures come from Vodafone's explainer. Service figures come from Ofcom's complaints data and Comparing Customer Service report.