Cookies on the SIM Sherpa website

We use cookies to track which pages on our website readers visit most. This helps us understand which topics people find interesting, to write more articles about them.

You can accept these tracking cookies or choose to block them. You can change these settings at any time.

X close

✖ Tracking cookies deleted and blocked

Ok, we will not track your page views as you move around any part of the SIM Sherpa website. But we will use that one cookie to remember you don't want to be tracked.

Click here to unblock tracking cookies

X close

✔ Cookies accepted

Thank you for accepting cookies for the SIM Sherpa website. This will help us constantly improve our content.

If you ever want to change your cookie settings for our website, go to our Cookies page here.

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

SMARTY and iD Mobile logos

The retailers featured on this page may compensate us when our readers follow links to their websites and make a purchase. More

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 July 2020.

In our SMARTY vs iD Mobile guide

Offer notifications

iD Mobile's hidden £5 offer

iD Mobile banner

Use our special link below to get a hidden offer, not advertised directly at

1GB data, unlimited texts & mins, £5 a month (1‑month contract)

See all SIM only offers (opens in new tab)

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

The coverage is identical on iD Mobile and SMARTY

Powered by Three banner

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.

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
(opens in new window)

iD's network map

iD Mobile coverage checker screenshot

Check iD signal

using their coverage checker
(opens in new window)

Our verdict on coverage:

No current winner

"Until either of the providers launches their 5G services, their coverage in the UK is identical, because they both use the same Three mobile network. This isn't something to influence your decision."

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

iD Mobile 4G speeds

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.

We expect SMARTY to launch 5G data first

SMARTY 5G news banner

Read latest 5G news

(opens in new window)

When 5G gets into full swing across the UK, it's going to make a huge difference to the data speeds on every network. In theory, the top speed of 5G is up to 1 Gbps (50x the typical 4G on Three today).

We've got a feeling that being owned by Three directly might be an advantage for SMARTY over iD Mobile. SMARTY have already announced they'll be launching 5G. iD have not.

Could we see Three turn the screw on SMARTY's low-cost competitor iD Mobile, who are owned by Carphone Warehouse, by not letting them have 5G for a few years?

These all come with 5G data already active:

We don't know. But we saw this happen with other providers when 4G first launched, so we wouldn't be surprised. The beauty of 1-month contracts is you don't have to wait around if you get fed up waiting for 5G.

Useful link: More about 5G on SMARTY

Our verdict on data speeds:

No current difference

"Prior to either provider offering 5G before the other, we don't think speed differences should be a factor in deciding between iD Mobile and SMARTY"

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

iD have better extras for boosting indoor call signal

iD Mobile WiFi calling banner

Check supported phones

(opens in new window)

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.

iD Mobile support both 4G calling and WiFi calling on all their pay monthly phone and SIM only contracts. This is something SMARTY do not offer, despite their parent Three having an excellent scheme themselves.

WiFi calling works by letting your phone tap into iD's mobile network via WiFi instead of regular 3G for calls/texts (check iD support your phone here) - meaning you can still use your phone as usual.

4G Calling is similar. It allows your phone to make calls over 4G, instead of just 3G like normal calls. That gives you better calls coverage indoors and outdoors and brings the benefit of HD audio quality too (check iD support your phone first here though).

Useful link: See all networks with WiFi calling

Neither has any free WiFi hotspot networks

SMARTY WiFi hotspot FAQ

Read the FAQs

(opens in new window)

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:

Clear win for iD Mobile

"Anyone who has struggled with poor indoor signal will know that iD Mobile having WiFi/4G calling is a huge advantage over SMARTY for staying connected at home and elsewhere. SMARTY need to catch up fast."

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

Some SMARTY plans pay you back the cost of unused data

SMARTY discount for unused data

How it works

(opens in new window)

If you only use a moderate amount of monthly data, SMARTY's strongest selling point is their data discount scheme, which effectively pays you back what you paid for any data you don't manage to use each month.

You'll need to join on one of their Data Discount plans (see below). And then at the end of the month, SMARTY calculate what you've not used and how much it cost and discounts next month's plan by that amount.

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

(opens in new window)

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, even if it's not quite as good as getting hard cash off your next month's bill like on SMARTY.

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

Our verdict on unused data:

Minor win for SMARTY

"If you've got too much data in your plan, there might not be a point in stacking it up for next month on iD. We think people will prefer getting their money back with SMARTY."

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

(opens in new window)

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

(opens in new window)

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

(opens in new window)

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

(opens in new window)

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

(opens in new window)

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

(opens in new window)

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

iD's affordable SIM only deals

iD Mobile 1GB £5 SIM banner

See all deals

(opens in new window)

iD Mobile are always among the cheapest mobile networks for the lower data plans. This month they've got a couple of reasonably competitive deals:

Useful link: All iD Mobile's special offers

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
Deal options >
Mins, texts and data >
Data speed (4G or 5G) >
Max contract length >

Close options








Minimum data speed


Maximum contract length

1 month
12 months

Close filters

Choose which networks you'd consider:

Three logo
BT Mobile logo
EE logo
giffgaff logo
ID logo
Lebara logo
O2 logo
Plusnet Mobile logo
Sky logo
Talkmobile logo
Tesco logo
Virgin Mobile logo
Vodafone logo
VOXI logo

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

iD Mobile order process

What gets checked

(opens in new window)

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

(opens in new window)

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

(opens in new window)

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

Related articles

Full iD Mobile review

iD logo and a thumbs up

Full SMARTY review

iD logo and a thumbs up

SIM Sherpa can help you find your next SIM only deal

network logos