Smart eSIM

...Smart SIM? (First impressions)

Martin Brophy

Honest customer

7 min read

Apr 8, 2025

My iPhone is capable of supporting multiple eSIMs as well as a physical SIM card. The eSIM I use as my primary is an unlimited data plan with EE, which works well and is generally reliable. EE even offers signal on the London Underground, so my experience has mostly been positive. However, like all mobile providers, there are occasional black spots.

I’ve used the EE eSIM for over a year and have even upgraded my iPhone and successfully moved the eSIM from my older phone to the new one. A big benefit of eSIM-compatible phones is the ability to have a second line—some people use this for work, but I was keen to use it as a secondary data line to reduce the risk of being left without a data connection, particularly in areas where my primary network drops out. In the past, I’ve struggled with things like being unable to pay for parking due to no signal, despite other networks having coverage. If you can find a low-cost second data option, it’s definitely worth setting up.

Last year, I signed up with Y Mobile, which offered 2GB of data for £2/month—ideal for emergencies. I even wrote about it at the time, but they shut down shortly after, claiming to be a beta. Since then, I’ve been on the lookout for a worthy replacement.

After quite a bit of searching, I came across an alternative called the Smart eSIM from Honest Mobile. It’s a different concept: this eSIM acts as a smart backup for essential apps and only activates when your primary network loses data. It connects to EE, O2, Three and Vodafone, giving you four-network coverage in one solution.

“EE, O2, Three and Vodafone all in one backup SIM—finally a solution for those frustrating black spots.”

The apps covered include essentials like iMessage (text only), WhatsApp (messaging and voice), banking apps, navigation, parking and news apps. You can’t make traditional voice calls, but you can use WhatsApp to call over data. The Smart eSIM gives you unlimited data access for supported apps, and by limiting it to 500+ apps, it remains affordable and efficient—perfect for emergencies or travel.

It also includes international roaming at no extra cost, which is a great benefit when abroad. From my research, the list of supported countries is extensive. I think this could prove invaluable on future trips.

Unbeatable UK signal and free global roaming on the ultimate second SIM

Connect to EE, O2, Three & Vodafone
Free data roaming in 180+ countries
500+ supported apps only

Get Smart SIM

“£45 a year for a backup SIM with roaming included? That’s an absolute bargain.”

Pricing-wise, you can pay monthly at £10, but the best value by far is the annual plan at £45. It made more financial sense for me to go straight for the annual deal rather than test it monthly. If it does what it claims, it will more than pay for itself the first time I avoid being stuck without signal.

Some people online seem to misunderstand the product. It’s not a full secondary data SIM, and it’s not meant for browsing, streaming, or downloading. But if you want a clever and cost-effective way to stay connected for critical tasks, it could be just what you need.

“This isn't for streaming or browsing—it’s a clever backup for when your main line lets you down.”

The key to a smooth experience is understanding the setup. You need to keep your primary SIM set for calls and data, while configuring the Smart eSIM to kick in only when no data is available on your main network. Done properly, the transition is automatic and seamless—you may not even notice unless you’re watching your signal bars.

The support from Honest Mobile has been excellent. I received helpful setup emails, guidance on shortcuts (like how to simulate switching to the backup by turning off Wi-Fi), and there’s an app to manage everything. I even suggested an app (StartRescue) and it was added within a couple of weeks—a clear sign they’re listening to users.

“I suggested a new app and it was added within weeks—they’re genuinely responsive to feedback.”

All with unlimited data.
‍More apps added every week.

Search apps

Messaging
+ more
Navigation
+ more
Finance
+ more
Travel
+ more
Search
+ more

I also made a folder on my iPhone of all the compatible apps, and even discovered a few new ones in the process. I’d love to see a future feature that shows how many times the Smart eSIM has kicked in—that would be great to measure its value at renewal.

I haven’t yet tested the overseas roaming, but I’ll report back after my next trip. Overall, I’ve been impressed with how easy it was to buy, activate and use the Honest Smart eSIM. My expectations are high, and I’m looking forward to better coverage and fewer headaches when signal drops on my main line.

Keeping you connected

From commute to countryside and across continents

No more lost signal on your commute

Send WhatsApp messages, keep tabs on train times, and map to your next destination without disruption

No more lost signal on your commute

“My new work route has so many blackout spots... Smart SIM fixes that. It’s been a no-brainer lifesaver and can only get better. I couldn’t recommend enough!”

Daniel

Peace of mind about staying connected

From city to the countryside

Peace of mind about staying connected

“I was right out in the sticks, my network had lost all bars and I was lost. So I switched to my Smart SIM and boom! Enough service to get maps to show me the right direction. I truly do thank my Smart SIM for saving me!”

James

Say goodbye to expensive roaming

Roam free in 180+ countries with no extra costs

Say goodbye to expensive roaming

“As soon as I turned off airplane mode, Smart SIM kicked in and I had maps, messages, and data in seconds. I found my route, messaged the hostel, and got there without stress. I couldn’t believe how easy and reliable it was. Total lifesaver.”

Mari

Got a question?
We’ve got the answer

What is Smart SIM?

Smart SIM is a data-only eSIM that works alongside your main SIM to give you peace of mind for your signal.

📶Better UK signal – 500+ essential apps with unlimited data on EE, O2, Three or Vodafone when your main SIM loses signal

🌎Free global roaming – those same 500+ apps with unlimited data in 180+ countries

So whether you’re deep in the countryside, mid-commute, or holidaying in Cameroon, Smart SIM keeps you connected when it matters most.

Set up once and it’s there whenever you need it. No more bad signal, dodgy wifi or expensive roaming fees 👋

How do I use 500+ apps on Smart SIM when I lose signal or go abroad?

Easy. Switch to Smart SIM in just a few taps or wait for it to kick in when your main SIM completely loses signal.

Is roaming on Smart SIM completely free?

Yes, from South Africa to Sri Lanka, Italy to India, Smart SIM has got your essential apps covered in 180+ countries (see the full list of available countries here). No hidden costs or scary bills to worry about while you’re away.

You’ll need to hop onto wifi for activities like web browsing or streaming.

Why isn’t every network offering a SIM like this?

Good question. We’ve always done things differently at Honest on our mission to build the best mobile network on the planet.

After introducing Classic SIM to thousands of happy customers, we still felt signal and roaming could be better. So we developed Smart SIM.

How much is Smart SIM?

Smart SIM is £10/month on our 30-day plan, or £45 for the year if you choose our annual plan (that’s just £3.75/month 😮).

Can I use Smart SIM as my main SIM?

We love your enthusiasm, but it’s a no. You'll need your main SIM for calls and texts, social media and streaming, and web browsing.

Smart SIM works alongside your main SIM, kicking in when you lose signal or go abroad. Think of it as your trusty back-up, there when you need it most.

Which apps can I use with Smart SIM?

All the most essential ones: WhatsApp, Google Maps, Uber, Citymapper, Monzo… the list goes on. You can see all 500+ apps Smart SIM works with here.

We’re adding more apps every week, so stay tuned 👀

Is data really unlimited for the 500+ apps?

It sure is. Consider it the all-you-can-eat buffet for apps including WhatsApp, Google Maps, Uber, Monzo and many more 📱

Can I call and text with my Smart SIM?

You can WhatsApp call and message, but if you're going old school, you'll need your main SIM for texts and calls.

Can I get a physical Smart SIM?

No, although this might change if enough people want it to. We created Smart SIM as a second SIM – as most phones only have one slot for a physical SIM, it’s eSIM only for now.

Because Smart SIM is a digital eSIM, you can add it to your phone and set up right away.

Just make sure your phone is eSIM compatible before ordering.

How do I get a Smart SIM?

We thought you’d never ask! Click here to get your Smart SIM – you’ll be up and running quicker than you can say ‘better signal and free global roaming’.

Is Smart SIM the same as Classic SIM?

No. Classic SIM is your essential everyday UK SIM for texts, calls and data. It piggybacks on Three’s network.

Smart SIM is the ultimate second SIM, working alongside your main SIM (on any network) to give you 500+ apps on EE, O2, Three and Vodafone and in 180+ countries around the world.

For the ultimate peace of mind when it comes to your signal, we recommend using both.

Can I use a VPN with Smart SIM?

No, and you don’t need to. Smart SIM is a VPN by default and fully secure. Think of it as a digital fortress for your data 🔒

Can't I use social media or streaming apps?

Afraid not. To keep Smart SIM affordable, we’ve limited it to apps that don’t gobble up endless data. That means social media and streaming are off the cards (for now, at least).

On the flip side, you have more than 500 apps (and counting) at your fingertips, whether you’re on the train, on your travels or out on the town. Plus, it’ll give you a break from all that doomscrolling 😉

...Smart SIM? (First impressions)

Easy as 1,2,3

Keeping you connected

Plans

Plans

Got a question?
We’ve got the answer

...Smart SIM? (First impressions)

Easy as 1,2,3

Keeping you connected

Plans

Plans

Supported countries

Unlimited data on supported apps

Connect to EE, O2, Three and Vodafone

Got a question?We’ve got the answer

Got a question?
We’ve got the answer