Mobile · Head to head
giffgaff vs Smarty SIM-only: which costs less?
The quick answer
On 27 Oct 2026, giffgaff's best-value deal is 5GB monthly rolling at £8.00 a month real cost and Smarty's is 5GB rolling monthly at £6.00. Smarty is cheaper by £2.00 a month on its best-value deal, with fees and stated price rises counted.
Best value from each 27 Oct 2026
Affiliate
14 deals · best value first
Every deal from both, ranked by real cost
AffiliateRanked by real cost: setup fees and every stated price rise in, reward cards out. Prices checked on each provider's own site, 27 Oct 2026.
Leaving early
What it costs to leave each one early
Leaving giffgaff early
18-month contract plans: 50% of the cost of your current or most recent plan x full months left. Monthly rolling plans: no commitment, cancel any time.
giffgaff's own formula: (cost of your current plan / 2) x months left in your contract.
Notice: not published (monthly plans: turn off auto-renew)
The big difference
The big difference is the network: giffgaff runs on O2, while Smarty runs on Three. Brands on the same network share its coverage, so check coverage at your address first.
Contracts differ too. giffgaff offers 30-day rolling plans and 18-month plans. Smarty offers 30-day rolling plans only. A 30-day plan lets you leave with a month's notice or less.
Both brands include EU roaming on the plans in our table, but Smarty's comes with a 12GB fair use limit. On price rises, giffgaff has no mid-contract rises on 18-month plans bought before the end of 2026, and Smarty has no annual rises. Since 17 January 2025, Ofcom rules say any price rise in a new contract must be stated in pounds and pence when you sign. Percentage and inflation-linked rises are banned in new contracts.
Choose giffgaff if
You want O2 coverage, an 18-month contract, or the extra data on offer.
- You want O2 coverage. giffgaff runs on the O2 network, while Smarty runs on Three.
- You want an 18-month plan with no mid-contract price rises. giffgaff offers this on 18-month contracts bought before the end of 2026. Smarty plans in our table are 30-day rolling.
- You want extra data now. giffgaff lists 25GB plus 55GB extra free if you activate by 30 October 2026.
Choose Smarty if
Smarty suits you if you want a rolling 30-day SIM with no annual price rises.
- You want to leave easily. Smarty plans are 30-day rolling, so you can leave with a month's notice or less.
- You want Three network coverage. Smarty runs on Three, and every plan includes 5G. See Smarty SIM-only.
- You use your phone in the EU. EU roaming, which means using your UK allowance there, is included, with a 12GB fair use limit.
Straight answers
Questions people ask
- Is giffgaff cheaper than Smarty?
- The cheaper option is whichever plan has the lower real cost, and we rank giffgaff and Smarty plans side by side. Real cost counts every monthly price, every stated price rise and any setup fee, averaged over the contract. Compare plans of the same length, then see the lowest real costs in our cheapest SIM-only deals.
- What network do giffgaff and Smarty use?
- giffgaff runs on the O2 network, and Smarty runs on the Three network. Every UK SIM-only brand uses one of four networks: EE, O2, Vodafone or Three. Brands on the same network share its coverage, so check which network has the best signal where you live.
- Can I switch from Smarty to giffgaff and keep my number?
- Yes, you can keep your number when you switch from Smarty to giffgaff. Text PAC to 65075 to get your switch code, then give it to giffgaff, and your number moves in one working day. To leave Smarty without keeping your number, text STAC to 75075 instead.
Keep comparing
Your next question, answered
- giffgaff SIM-onlyEvery giffgaff SIM-only plan we track: data, contract, network and the real cost after stated price rises, read from giffgaff's own site daily.
- Smarty SIM-onlyEvery Smarty SIM-only plan we track: data, contract, network and the real cost after stated price rises, read from Smarty's own site daily.
- Cheapest SIM-onlyThe cheapest SIM-only deals on every UK network, by real cost after stated price rises. 30-day and contract plans, checked daily.