Travelling to the USA
Help and support
Travelling to the USA | Help & Support | O2
Calling from the USA
From 2023, you’ll be unable to use your UK mobile phone to make regular calls when visiting the USA because of changes to their mobile networks. However, you’ll be able to use your phone to make calls using the 4G network – provided you have a compatible phone.
Follow the steps below to check whether your phone is compatible or you can find a list of compatible devices here.
Step 1 - Find your IMEI number

The International Mobile Equipment Identity (IMEI) number is a unique 15-digit code that precisely identifies your mobile phone.
Key *#06# into your phone keypad.
This will reveal a series of numbers, one of which is labelled IMEI.

Make a note of the first 8 digits of the number, in this example that would be:
35335767
You can also find your IMEI number in the settings on your phone.
- Settings for iPhone
iPhone - go to Settings > General > About. The IMEI number is listed in a section called PHISCAL SIM. Make a note of the number or use the copy function on your phone.
- Settings for Android
Android - go to Settings > More > About device > Status. The IMEI number is listed along with other information about your phone. Make a note of the number or use the copy function on your phone, if it has this capability.
Step 2 - Check your IMEI
Enter the first 8 digits into the field below. Or you can copy and paste the full number from the settings on your phone.
Step 3 - Set up 4G Calling abroad
Click the link corresponding to your phone model to find out how to set up 4G calling abroad.