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iD Mobile vs SMARTY: the two cheap networks on Three compared

SMARTY and iD Mobile logos

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Both SMARTY and iD Mobile use the Three network. But which offers the best all-round experience and benefits with their plans? SIM Sherpa is your trusty guide. Last updated: 1st June 2021.

In our SMARTY vs iD Mobile guide

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SMARTY's vs iD Mobile's networks

Is coverage the same on iD Mobile and SMARTY?

We check whether there's any signal differences between them

Mobile signal bars with iD and SMARTY logos

4G/3G coverage is identical on iD Mobile and SMARTY

Powered by Three banner

What this means...

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Both SMARTY and iD Mobile use the Three network. SMARTY are actually owned by Three themselves, while iD Mobile are owned by Carphone Warehouse. You get 4G and 3G signal on both (but no older 2G for calls).

Overall, Three is the smallest UK network but someone has to be. They still get their 4G to over 97% of UK residences outdoors and calls to over 99% and are still improving both and indoors.

We've tested a SMARTY and a iD Mobile SIM against each other and against a Three one in a city, a medium town and the countryside. We found no difference in the number of bars you got with each provider.

Away from large cities, the 4G and calls coverage isn't universal. So we do advise checking signal with either network here before you sign up, to make they've got 4G/3G in all the places you plan to take your phone.

Useful links: Our full SMARTY review | Our full iD Mobile review

iD now offer 5G data on selected phones

iD 5G banner

Check supported phones

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Despite what we were expecting, iD Mobile have actually beaten SMARTY to offering 5G. You'll get it free with any pay monthly plan you choose, whether it's SIM only or a phone contract.

They are being a bit cagey about what phones it will work on. It's not just whether your phone has 5G as a feature but whether they've specifically rolled out their 5G settings to the manufacturer, so check this list.

But otherwise you can look forward to 5G data in all the places Three have it. That's a total of 192 locations so far (see them all and rollout plans here on Three's website).

5G coverage on the network is still very much on a street-by-street basis though, it's not like the entire listed location can get 5G. But either way, until SMARTY add the feature, it's advantage iD Mobile.

Useful link: Our guide to the best 5G networks

Check signal with either provider

Don't just test coverage where you live - but everywhere you'll take your phone

SMARTY's network map

SMARTY coverage checker screenshot

Check SMARTY signal

using their coverage checker
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iD's network map

iD Mobile coverage checker screenshot

Check iD signal

using their coverage checker
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Our verdict on coverage:

Technically a win for iD

"For 3G and 4G, we're confident there's no difference between iD and SMARTY. But as iD have 5G and SMARTY do not, that is technically an advantage on coverage."

Compare pricing and deals

Download speeds on SMARTY vs iD Mobile

Is either provider faster than the other?

iD Mobile and SMARTY logos with a speedometer

We've found no built-in speed differences between SMARTY and iD

SMARTY 5G news banner

Read latest 5G news

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Independent speed testers Opensignal and Speedtest by Ookla measure both providers' host network Three's typical 4G download speeds at 22.4 Mbps (Opensignal) and 20.39 Mbps (Ookla).

Those kinds of speeds on average opens up demanding stuff like streaming videos in HD without buffering and is like a mid-range home broadband connection. Speeds do go lower and higher in different locations though.

We've tested an iD Mobile, SMARTY and Three SIM in a number of locations in the same model phone and found there to be no sign of built-in speed differences with either provider.

There were short fluctuations in the speeds we measured but we couldn't find any speed caps on either network. And there's nothing about them in SMARTY or iD Mobile's terms and conditions.

The only speed difference will be if you have a supported 5G phone and you're in a 5G area. As only iD have the newer technology enabled, you'll only benefit from the improved speeds (around 196.02 Mbps) with them.

Useful link: SMARTY's latest progress on 5G

Our verdict on data speeds:

Another technical win for iD

"For most your usage up and down the country, there will be no speed difference between them. But iD having 5G means, they do technically have the upper hand in certain locations."

Compare pricing and deals

Extra network features on iD Mobile vs SMARTY

Who has better extras to keep you connected?

Gears icon with SMARTY and iD Mobile logos

Both SMARTY and iD now have WiFi calling

iD Mobile WiFi calling banner

Check supported phones

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All mobile networks can encounter problems getting their signal for calls indoors. And Three's 3G calls signal is broadcast on frequencies that can find it harder than average. So there's extra technology to help out.

Both iD and SMARTY now support both WiFi calling and 4G calling (VoLTE), so this is no longer a difference between them (for a long while only iD had them out of the two).

There is a difference in the precise models each provider reports that they support. So check yours is on iD Mobile's list here and/or SMARTY's list here. SMARTY's seems defensively short, like others may work but haven't been tested.

WiFi calling lets your phone use WiFi to make/take calls and send/receive messages if there's poor indoor signal. And 4G calling improves audio quality and increases coverage by utilising 4G signal on top of 3G. So both are a benefit.

Useful link: See all networks with WiFi calling

Neither has any free WiFi hotspot networks

SMARTY WiFi hotspot FAQ

Read the FAQs

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If your aim is to buy the cheapest plan possible with the least data you need, it's handy when mobile networks offer free automatic WiFi hotspot access on your mobile, to save your allowance for when you need it.

Neither iD Mobile nor SMARTY offer any free WiFi provision, not even on London's Underground network like SMARTY's parent Three get you. So it's not a difference to consider.

There's loads of free WiFi hotspot provision about nowadays anyway, so this is less important than it once was. And if you're concerned about going over limits, both iD and SMARTY have unlimited data plans:

Useful link: SMARTY's hint they may offer it in future

Our verdict on network extras:

No overall winner

"Now that SMARTY have added WiFi calling to all their plans, iD no longer have the advantage for extra network features they previously held."

Compare pricing and deals

Benefits on SMARTY vs iD Mobile

Unused data schemes: iD Mobile vs SMARTY

Which has the best system for data you've not managed to use?

Arrows in circle with SMARTY and iD Mobile logos

A few SMARTY plans pay you back for unused data

SMARTY discount for unused data

How it works

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When SMARTY were first launched, their key unique selling point was that they'd pay you back any data you didn't manage to use, at the same rate as you bought it for - so you'd never be out of pocket.

This still exists as a benefit but it's now limited to just a few plans, rather than SMARTY's whole range. And you can actually get better pricing per GB data if you don't want the payback feature. See the dropdown below:

These all pay you back for unused data:

At the end of each month, SMARTY count up the data you've got left, calculate how much it cost you to buy in the first place (£1 per GB) and then discount your next month’s plan by that amount.

They don’t just look at whole gigabytes. They even look at the smaller megabytes to make sure you get back every penny. For us, this is the fairest unused data scheme in the UK.

Useful link: Read our full data discount review

iD Mobile let you keep unused data for next month

iD Mobile data rollover banner

Read full guide

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People's data usage varies month-to-month, which can make choosing your plan tricky. Buy too big a plan and you waste money if you never hit your limit. Buy too small and you'll have to pay for going over your limit.

iD Mobile let you keep any data you don't use one month, to use in the next month (after that you do lose it though). It's called data rollover and quite a few other networks now offer it too.

It takes some of the pressure out of picking a plan. For example, imagine you know your usage averages around 1GB. You can take a 1GB deal and if you use 800MB one month, you'll have 1.2GB to use next month.

We think people with small and moderate amounts of data in their plan will appreciate this iD benefit most. And it comes on every plan, which is an advantage over SMARTY.

Useful link: Full guide and FAQs on iD's data rollover scheme

Our verdict on unused data:


"On paper, SMARTY's scheme is better but you only get it on a few plans nowadays. iD's is universal to all their pay monthly deals, so more people will benefit."

Compare pricing and deals

Roaming compared on SMARTY and iD Mobile

Which network is better for going abroad?

A globe with SMARTY and iD Mobile logos

SMARTY give you straight-forward inclusive EU roaming

SMARTY free roaming banner

Full roaming costs

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You can take your SMARTY plan to any of these countries within the EU and EEA and use your unlimited minutes and texts and your entire data allowance without paying extra (up to 19GB on the unlimited plan).

What's disappointing is that you'll only get 3G data while you're abroad (same as iD Mobile), meaning you might not be able to do some of the more data-heavy activities you do at home.

One other thing to note on SMARTY is that you have to manually change some settings on your phone to configure roaming on SMARTY (here's how you do it). This could cause you problems if you're already abroad.

If you're going outside the EU, roaming can get pretty expensive fast on SMARTY. And you have to top up with credit, to pay for your usage at these rates while you're there. There's no inclusive worldwide roaming like Three's.

Useful link: SMARTY's guide to roaming on their network

iD Mobile have a fiddly roaming fair usage policy

iD roaming fair usage policy

Read fair usage policy

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There are a few differences between SMARTY and iD Mobile's roaming. But one thing that's the same on both is that you'll only get 3G data speeds while abroad.

In theory, iD Mobile do include a few extra roaming destinations you don't get on SMARTY. But before you get too excited those places are Azerbaijan, Belarus, Macedonia and Kazakhstan, so hardly holiday hotspots.

iD have also been a lot less generous with their inclusive EU roaming too. They operate a fiddly fair usage policy dictating how much of your data you can use there, depending on how much your plan costs.

But at least their roaming will normally just work immediately on your phone without having to fiddle with settings like you do on SMARTY.

Useful link: All roaming costs on iD Mobile

Our verdict on roaming:

No clear winner

"Roaming isn't particularly the strength of either SMARTY or iD Mobile. Both schemes have weakpoints: iD's is the fair usage policy, SMARTY is having to manually change settings. We'll let you decide which you can deal with."

Compare pricing and deals

Spending caps: iD Mobile vs SMARTY

Which has the best ways of stopping you overspending?

Wallet with SMARTY and iD Mobile logos

iD let you set flexible spending caps

iD spending cap banner

Learn more

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Every pay monthly mobile network now has to offer you the ability to set a cap on how much extra you're willing to spend above the regular cost of your plan. But iD have offered this for ages anyway.

Their Capping scheme comes as a benefit on every pay monthly phone or SIM only plan. It lets you set a cap anywhere between £0 and £25 in steps of £1. Or no cap. That makes it one of the most flexible.

If you try to do anything on your phone that would cost you more than your overspending cap, iD will automatically prevent your phone from doing it, so you won't rack up extra bills.

You can continue to use anything else like your plan's normal minutes, texts and data that wouldn't cost you anything extra. You can even change your cap mid-month if your current cap isn't quite right.

Useful link: Costs for extra usage on iD Mobile

SMARTY plans automatically stop you overspending

SMARTY no more unexpected bills banner

Read why

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SMARTY's plans also stop you overspending but in a slightly different way to iD Mobile. That's because you pay everything up front on SMARTY rather than receive a monthly bill.

You register a credit or debit card with SMARTY when you sign up and the cost of your monthly plan is charged to that up front. If you want to do anything that costs extra, you must first top up with credit (like pay as you go).

As a result, if you never want to be able to overspend more than your regular plan, just never bother topping up. That way, there's no credit on your account to be used for extras.

The downside of this is that you manually have to top up if you ever want to use something extra. You can't just set a cap of a few pounds and have your usage charged to a bill. Once you've topped up with credit, you also can't limit how that gets used up.

Useful link: More about billing on SMARTY

Our verdict on spending caps:

Minor win for iD Mobile

"If you want to be able to spend literally nothing extra, there's no difference between the networks. But if you want to leave a little headroom, iD offer the simplest way to do so."

Compare pricing and deals

Customer service: differences between iD and SMARTY

Which network has better customer service?

Customer service headset with SMARTY and iD Mobile logos

iD Mobile have more ways to contact them

Ofcom complaints data

Read report

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According to the government telcoms regulator Ofcom, iD Mobile are one of the least-complained-about mobile networks in the country (SMARTY don't have enough customers to appear in this data).

iD have really cleaned up their act in the last years, with a steadily improving record. We think this is partially down to their excellent iD Mobile account app, which lets you manage practically everything.

Unlike a lot of other low-cost providers, including SMARTY, you can ring iD Mobile. You've also got the option of Carphone Warehouse stores. And they have online chat.

If you like speaking to a real person when you want to know about something or have a problem, you're more likely to be comfortable on iD Mobile than SMARTY.

Useful link: All ways to contact iD Mobile

SMARTY offer online-only help

SMARTY mobile online chat screenshot

How to get help

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One of the ways mobile networks like SMARTY keep their costs down is by having as small a number of employees as possible. This includes in their customer services department.

As a result, you can only first contact SMARTY online, via their online chat function or their social media team. This isn't always a quick process. Sometimes you won't get a reply until the next day.

There's very little to go wrong on SMARTY in the first place, because their deals are so simple. But we do think this will be frustrating to people less confident at self serving.

It's one of the clearest points of difference between iD and SMARTY.

Useful link: How to get help on SMARTY

Our verdict on customer service:

A win for iD Mobile

"When iD and SMARTY are so similar in loads of other areas, having loads more ways to contact iD Mobile will be important to many customers."

Compare pricing and deals

Prices and plans compared

Special offers on SMARTY and iD Mobile

Here's what's currently running on the two networks

iD Mobile and SMARTY logos with a special offer tag

SIM only deals on iD Mobile vs SMARTY

Compare latest prices on their SIM only plans below

SIM card with iD Mobile and SMARTY logos



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Added features

iD Mobile's SIM only plans need you to pass a credit check

iD Mobile order process

What gets checked

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All of iD Mobile's pay monthly SIM only plans require you to pass a credit check before you can take one (here's iD's guide to what they're looking into with their checks).

That's because they need to make sure that you will be a reliable bill payer. And that you're not someone who will rack up big bills and then refuse to pay.

This is a standard practice on practically every pay monthly network. For most people this won't be a problem. But if you do have any history of defaulting on bill payments for any service you may find it hard to join.

Their pay as you go SIMs do not have a credit check, because all your usage is paid for up front. Compare all no credit check SIM only plans here.

Useful link: Full guide to iD Mobile's credit checks

SMARTY don't do a credit check

SMARTY no credit checks banner

How billing works

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It's a lot easier to get a SIM only plan from SMARTY. As long as you've got a UK debit or credit card, you can join. There's no credit check to pass.

Instead you register a card and your monthly plan is charged onto that. If you want to do anything that would cost extra, you have to pre-pay for credit or an add-on.

This system means that SMARTY can never get into the situation where someone racks up a bill and then refuses to pay.

The result of that is that they don't need to run a credit check on new customers. So if you've been declined before, SMARTY may be a better choice than iD Mobile.

Useful link: SMARTY's guide to billing on their network

Our verdict on SIM only plans:

Depends on current offers

"We think most people looking to join SMARTY and iD Mobile are just looking for the best value per minute, text and GB data. That varies month-to-month, so it's hard to pick an overall winner."

Compare pricing and deals

Phone contracts on iD Mobile and SMARTY

Do they both offer pay monthly handset deals?

iD Mobile and SMARTY logos with a phone

Only iD Mobile has phone contracts

Screenshot of iD Mobile phone range

Compare phone contracts

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SMARTY have been set up as a low cost SIM only plan provider and so don't do phone contracts at all. And we doubt they ever will. So out of the two, iD Mobile are the only choice.

Thanks to being owned by Carphone Warehouse, iD have a massive range of phones, including the Apple and Samsung models you'd expect. Their general pricing is lower than average.

iD's phone contracts are on straightforward 24-month terms - there's no complicated financing arrangements, just a monthly cost for your minutes, texts, data and the phone itself.

If you want a simple, low-priced phone deal with all the benefits we've described in all the other sections of this page, you could do worse than consider iD Mobile.

Useful link: See iD's range of phone contracts

Our verdict on phone contracts:

Automatic win for iD

"If you want a contract for a phone, iD are the only choice out of the two - so they win by default."

Compare pricing and deals

More iD Mobile guides

More SMARTY guides

More mobile network reviews