Last updated: Thursday 29 October 2026
SMARTY's £6 plan comes with 18GB instead of the usual 5GB, and Unlimited is £17 a month via SwitchSquid (£20 on SMARTY's own site), when we checked on 29 October 2026. Every SMARTY plan is a one-month plan on Three's network, with no annual price rises and no credit check.
Via SwitchSquid, SMARTY also had 40GB for £7, 50GB for £8 and 100GB for £10 a month on the same date. Below you'll find every plan side by side, who each size suits, how coverage and switching work, and how SMARTY compares with giffgaff. To compare every network, see our cheap SIM only deals page.
SwitchSquid may earn a commission if you buy through the buttons on this page. It doesn't change the price you pay.
SMARTY 18GB for £6 a month via SwitchSquid (usually 5GB), one-month plan
- 18GB of 5G and 4G data with unlimited UK calls and texts, £6 a month, checked 29 October 2026
- One-month plan, cancel or change anytime, no annual price rises
- Runs on Three's network: check coverage for your postcode first
Who SMARTY suits best
SMARTY runs on Three's network, so coverage comes first. If your home, workplace and the places you visit most get a weak Three signal, a cheaper price won't help. If Three works well where you live, SMARTY is a simple choice: one-month plans, paid in advance, with no credit check, no annual price rises and no long contract.
At the prices we saw when we checked on 29 October 2026, light users who are on Wi-Fi most of the day should start with the 18GB plan at £6 a month via SwitchSquid. Heavy users who stream, watch short videos on the go or use their phone as a hotspot should compare the 50GB plan for £8 and the 100GB plan for £10 with Unlimited at £17, all via SwitchSquid, and pick Unlimited only if they regularly run out of data. Families who need several lines should compare the price per line, and look at SMARTY's group plans on its own site, rather than assume one plan size suits everyone.
SMARTY plans compared
Prices below are from 29 October 2026. Rows marked "via SwitchSquid" are the prices shown on the SMARTY pages behind our buttons. The other rows are SMARTY's own price list. All plans include unlimited UK calls and texts.
Plan | Price | Data | Contract | Upfront | Code | Best for | More |
|---|---|---|---|---|---|---|---|
SMARTY 18GB (usually 5GB), via SwitchSquid | £6 a month | 18GB | 1 month | First month in advance | None needed | Light users on Wi-Fi most of the day | |
SMARTY 40GB, via SwitchSquid | £7 a month | 40GB | 1 month | First month in advance | None needed | Moderate users who want a low price | |
SMARTY 50GB, via SwitchSquid | £8 a month | 50GB | 1 month | First month in advance | None needed | Streaming on the commute | |
SMARTY 100GB (usually £12), via SwitchSquid | £10 a month | 100GB | 1 month | First month in advance | None needed | Heavy users and hotspot use | |
SMARTY Unlimited (£20 on SMARTY's own site), via SwitchSquid | £17 a month | Unlimited | 1 month | First month in advance | None needed | People who never want to watch a data counter | |
SMARTY 20GB | £9 a month | 20GB | 1 month | First month in advance | None needed | Light to moderate users | |
SMARTY 32GB (special offer, usually 16GB) | £8 a month | 32GB | 1 month | First month in advance | None needed | Moderate users buying direct from SMARTY | |
SMARTY 40GB | £10 a month | 40GB | 1 month | First month in advance | None needed | Moderate users | |
SMARTY 100GB | £12 a month | 100GB | 1 month | First month in advance | None needed | Heavy users buying direct from SMARTY | |
SMARTY 150GB | £15 a month | 150GB | 1 month | First month in advance | None needed | Very heavy users | |
SMARTY 200GB | £17 a month | 200GB | 1 month | First month in advance | None needed | Very heavy users | |
SMARTY Unlimited | £20 a month | Unlimited | 1 month | First month in advance | None needed | Unlimited data bought direct from SMARTY |
Links in the last column jump to sections on this page or open our related guides.
SMARTY 100GB for £10 a month via SwitchSquid (usually £12)
- 100GB of 5G and 4G data with unlimited UK calls and texts
- £10 a month via SwitchSquid; on SMARTY's own site the same 100GB plan is £12 a month, checked 29 October 2026
- One-month plan, cancel anytime; no annual price rises
- Runs on Three's network: check coverage for your postcode first
SMARTY £6, £8 or Unlimited: which size suits you?
The yearly maths is simple, using the prices we saw when we checked on 29 October 2026. The 18GB plan at £6 a month via SwitchSquid is £72 over 12 months if the price stays the same. Via SwitchSquid, the 50GB plan at £8 a month is £96, and 100GB at £10 a month is £120. Unlimited at £17 a month via SwitchSquid is £204 a year, against £240 at SMARTY's own £20 price. That gap is what you pay to stop watching a data counter.
Choose 18GB if Wi-Fi covers most of your evenings and weekends. Choose 50GB or 100GB if you watch video on the commute or use your phone as a hotspot most weeks. Choose Unlimited only if you already trust Three's coverage where you live and regularly run out of data on a capped plan.
Every SMARTY plan is one month, so picking the wrong size costs you one month at most. Start smaller if you're unsure, see how much you use in your first month, then move up at the next bill if you need to.
Three coverage, 5G, eSIM and roaming
Coverage and 5G follow Three's masts. Use Ofcom's mobile coverage checker, or SMARTY's own coverage checker, for your home and work postcodes before you move your number. 5G works where there's a 5G signal and your phone supports it.
When we checked on 29 October 2026, SMARTY's plan pages listed Wi-Fi Calling, physical SIM and eSIM options, and EU roaming with a 12GB fair use limit taken from your monthly allowance. If you travel outside the EU often, check SMARTY's roaming page for the country you're visiting before you go.
Switching with a PAC or STAC
To keep your number, text PAC to 65075 from your current phone. If you don't need your number, text STAC to 75075 instead. Under Ofcom's rules your current provider must reply within one minute, the code is valid for 30 days, and the switch must complete within one working day. Give SMARTY the code when you order, or later in your SMARTY account. Our PAC code guide has the full steps.
Keep your old SIM in your phone until your number moves across, so bank security codes still reach you during the switch. If you're leaving a contract early, check your current provider's early exit fee before you send the code.
SMARTY offers through partner links
Some SMARTY prices are only available through partner links like ours, such as 100GB for £10 or Unlimited for £17 when we checked on 29 October 2026. The plan page you land on may show a different headline price from SMARTY's main price list; the basket shows what you'll actually pay.
For example, the 40GB for £7 and 50GB for £8 offers open on SMARTY's smaller plan page, with the larger allowance shown at the top of the page. Read the plan name, data allowance and monthly price on the page before you pay.
SMARTY Unlimited for £17 a month via SwitchSquid (£20 on SMARTY's own site)
- Unlimited 5G and 4G data with unlimited UK calls and texts, £17 a month, checked 29 October 2026
- One-month plan, cancel anytime; no annual price rises
- Runs on Three's network: check coverage for your postcode first
SMARTY or giffgaff: which suits you?
giffgaff runs on O2, so the first question is which network works better where you live. SMARTY Unlimited was £17 a month via SwitchSquid on a one-month plan when we checked on 29 October 2026, so compare it with giffgaff's price and contract length before you choose. Our giffgaff vs SMARTY Unlimited guide and giffgaff Unlimited guide go into more detail.
SMARTY suits you if Three covers you well and you want to be able to leave any month. giffgaff suits you if O2 is stronger where you live. There's no single best choice for everyone: check coverage first, then decide how long you're happy to commit, then pick the data size.
How much data do you really use?
Open your current network's app and look at the last three months of data use before you pick a plan size. Someone who listens to podcasts on Wi-Fi needs far less data than a parent who runs a tablet hotspot on the school run. A weekend away with poor Wi-Fi can use far more than a normal week. If that only happens a couple of times a year, it isn't a reason to pay for Unlimited every month; on a one-month plan you can move up for that month and back down afterwards.
Watching video, especially in HD, uses the most data. Music and podcasts use much less, and messaging, maps and browsing use less again. Most phones let you set video to a lower quality on mobile data, which makes a smaller plan go further.
Credit checks, paying in advance and referrals
SMARTY's one-month plans have no credit check, and you pay at the start of each month. That helps if you're building a credit history, but it also means you need a working payment card every month. Set a reminder a couple of days before your plan renews.
SMARTY's site also offered up to a £20 gift card for referring friends when we checked on 29 October 2026. Treat it as a bonus rather than a reason to choose a plan, and read SMARTY's referral terms before you rely on it.
How we check these prices
We open SMARTY's own price list and the SMARTY page behind each button on this page on the date shown at the top, and copy the plan, data and monthly price as shown. We update this guide every month. Prices can change at any time, so check the plan name, data allowance and monthly price in the basket before you pay.
FAQ
What are the best SMARTY SIM only deals in 2026?
Via SwitchSquid, SMARTY's £6 plan comes with 18GB instead of the usual 5GB, 100GB is £10 a month and Unlimited is £17 a month, when we checked on 29 October 2026. On SMARTY's own site Unlimited is £20 a month. Every plan is a one-month plan on Three's network.
Does SMARTY use Three's network?
Yes. SMARTY runs on Three's network, so coverage and 5G follow Three's masts. Check coverage for your home and work postcodes before you switch.
What about SMARTY's bigger plans?
SMARTY's own site listed 32GB for £8 as a special offer (usually 16GB), 20GB for £9, 40GB for £10, 100GB for £12, 150GB for £15, 200GB for £17 and Unlimited for £20 a month when we checked on 29 October 2026. Via SwitchSquid, 40GB is £7, 50GB is £8, 100GB is £10 and Unlimited is £17. All are one-month plans.
Which SMARTY plan size should I take?
Look at your last three months of data use in your current network's app first. If you use well under 18GB a month, the 18GB plan for £6 a month via SwitchSquid is enough, when we checked on 29 October 2026; if you stream or use your phone as a hotspot, 50GB or 100GB gives more room. Because every plan is one month, you can move up or down at the next bill.
Can I keep my number?
Yes. Text PAC to 65075 from your current phone, then give SMARTY the code when you order or afterwards. Ofcom's rules say the switch should complete within one working day.
Does SMARTY have annual price rises?
No. SMARTY's plans are one-month plans with no annual price rises, when we checked on 29 October 2026. You can change or cancel your plan each month.
Is there a phone deal in this guide?
No. This guide covers SIM only plans, so you keep your current phone or buy one separately. Check your phone is unlocked before you order a SMARTY SIM.
