Turn off data for one of the sims

Hello Co_UK01,

Welcome to Apple Support Communities. We understand wanting to disable cellular data on one of the dual SIMs on your device, and we'd be happy to help.

While some feature, depending on the carrier may require a cellular connection, you can turn off cellular data to a specific line manually. This link will explain how:

Using Dual SIM with an eSIM - Apple Support

Under "Manage cellular settings"

Also, check out the "Apple recommended" section in the following thread:

How can I Disable one sim card on iPhone XS Max

We hope this information is useful. Kind regards.

Hello Co_UK01,

Thanks for getting back to us with those additional details. It looks like you don't have the option to turn off cellular data on one line for the dual SIM, and we'd be happy to get you pointed in the right direction to get some help.

In this particular situation, we'd recommend reaching out to your carrier for further assistance as each carrier handle these connections differently.

Thank you for using Apple Support Communities. Have a nice day.