Everything extra you need to know about Smart SIM. From how it works to troubleshooting and usage tips.
How it works
What is Smart SIM?
Smart SIM is a data-only eSIM that keeps you connected to 500+ essential apps, both in the UK and abroad. Switch to it in a few taps when your main SIM loses signal or when you're travelling.
Does Smart SIM replace my main SIM?
No. Smart SIM works alongside your existing SIM, it doesn't replace your number or affect your main plan. Think of it as a backup connection that kicks in when you need it.
How does Smart SIM work in the UK?
Smart SIM connects to the UK's major networks to keep you on essential apps when your main SIM loses signal.
How does Smart SIM work abroad?
Switch to your Smart SIM when you arrive in a supported country and you'll have access to 500+ apps without relying on expensive roaming or patchy hotel Wi-Fi.
Coverage, usage, and limits
Which apps work on Smart SIM?
Smart SIM supports a curated list of apps focused on travel, navigation, messaging, and essential services. You can see the full list here.
Why can’t I use social media or streaming apps?
Keeping Smart SIM affordable worldwide means focusing on essential, lower-data apps. High-usage apps like YouTube or TikTok would drive up costs for everyone.
Can I use data for other apps?
No, Smart SIM will only work for the approved apps. If you need full data access, check out our Classic SIM plans instead, which runs on the Three network.
Does Smart SIM come with a phone number?
It shows a US +1 number, but it's not active, you can't make calls or send texts with it. It's simply part of the technical setup.
Can I use the Smart SIM to call 999?
No. Since Smart SIM is data-only, emergency calls like 999 won’t work. Use your primary SIM for emergency calls, they’re free anywhere in the world.
Can the Smart SIM be used as a hotspot?
No, hotspot and tethering aren't supported.
Can I see my usage of the Smart SIM
Yes, you can view your Smart SIM usage in the app. Just tap your SIM to see your usage shown in the green circle.
Usage is recorded in chunks, so one “use” might be a one messages via WhatsApp or 10, it’s not exact, but we’re improving it all the time.
The data updates daily at 6am, starting from when you first installed the SIM.
Billing and compatibility
Is there an extra charge for using Smart SIM abroad?
No. International use is included in your monthly or yearly Smart SIM plan — no extra charges.
I already have 2 SIMs; can I still add the Smart SIM?
Most phones support a maximum of two active SIMs at once. You may need to turn one off to add Smart SIM, check your phone's settings or model specs first.
Setup and troubleshooting
How do I check if my Smart SIM is working?
Use the in-app connection test, tap your Smart SIM in the Honest app and select 'Test connection'. To find out more, click here.
Why can’t I use a VPN with Smart SIM?
The Smart SIM needs to see your connections to grant access to approved apps, so VPNs aren't currently compatible.
We're exploring ways to support VPN use in the future.
Does Smart SIM work on planes or at sea?
No, satellite, maritime, and in-flight networks aren't supported. You can check the full list of supported countries
Switching between SIMs
Can I switch to Smart SIM temporarily?
Yes. You can manually switch to Smart SIM whenever you need it and switch back just as easily.
Can I enable automatic switching between SIMs?
Yes, and we recommend it. Automatic data switching means Smart SIM kicks in on its own if your main SIM loses signal completely, without you having to do anything.