My SIM is not working

Follow this checklist to diagnose and troubleshoot the issue you’re experiencing.

Casey avatar
Written by Casey
Updated this week

Watch our handy video for things to check to get you back up and running 🚀


1. Check that you've activated your SIM ⚡

If you're new to us, your SIM won't automatically activate just by putting it in your phone.

If you ordered a SIM through our website, learn how to activate it here.

If you bought a SIM in-store, another retailer, or received one from a friend, and you haven’t created an account yet, learn how to activate this type of SIM here.

2. Turn your phone off/on or test your SIM in another device 📴

We know it's old school, but sometimes it doesn't hurt to restart your device. You might find it'll reconnect you to the network. 📡

Testing your SIM in another device can also rule out a SIM or device fault.

3. Check your phone is unlocked 🔓

Most devices purchased in the UK after 2021 should be unlocked.

Check out this article for details on unlocking your phone.

4. Are you using the right SIM card?

SIMs are small and fiddly, so they're easy to get mixed up. 🤏

Check your SIM card says 'SMARTY'.

You may have also received an extra SIM in your SMARTY SIM package, which is enclosed in a separate smaller envelope marked as “Bonus SIM”.

Your correct SIM will have been glued to the inside of the original packaging. If you're unsure, please contact our Customer Care Team and we'll be able to let you know which SIM you need to insert.

5. Check your device is connected to the SMARTY network 📡

If you're unable to use data, you may need to amend your APNs (Access Point Names). 📝

See this article for information on checking your Access Point Name (APN) settings.

6. Check you're using a 4G-VoLTE-compatible device

If we think you do not have a 4G-VoLTE compatible device, we will contact you a minimum of 30 days before the 3G switch-off date in your area, so you will have plenty of time to find a suitable replacement.

Find out more about saying goodbye to 3G here. 👋

7. Check the network status in your area 🗺

If you're struggling with your connection, our Network Status Checker will show any faults or maintenance that could impact your signal.

If there is a problem, don't worry, our network engineers will be on the case 👷‍♀️

8. Has payment for your latest renewal gone through? 💷

If your plan has paused, you'll have received an email to notify you. Incoming services such as calls and texts will still be available, however outgoing calls, texts and data won't be.

If you have auto-renew enabled and your payment fails, we'll attempt to re-take the payment again.

If you don't have auto-renew enabled, you'll need to log in and manually renew each month.

If payment hasn’t gone through, your account will be paused. Check if

  • Your payment method is valid

  • Your payment attempt was blocked by your card issuer

Once you’ve entered a valid payment method, follow this link to renew your plan.

9. In the process of switching your number to SMARTY?

Transfers should happen within 1-2 business days.

You may experience a little downtime when the transfer is taking place, so don’t worry if you lose signal, or you’re unable to make a call or send a text. This is perfectly normal and only temporary. 😊

You may also need to restart your device before everything starts working. You will receive a confirmation email when the port is completed.

See this article for more details on transferring your number.


Tried all that and still no luck? ☹

If your SIM still isn’t working, please contact our Customer Care Team via webchat.

We are available from 8am-8pm 7 days a week. Just look for the green chat icon 👇

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