Want to use Smart SIM as a backup method for your main SIM? Follow the steps below to ensure your phone automatically switches to the Smart SIM when your Primary SIM loses all signal.
Google Pixel devices
Open Settings
Tap Network & Internet > SIMs.
Select your Smart SIM.
Under Call preference:
Set your Primary SIM as the preferred SIM
Under SMS preference:
Set your Primary SIM as the preferred SIM
Under Mobile Data preference
Set your Primary SIM as the preferred SIM
Toggle Switch mobile data automatically on
Toggle Data Roaming on
Samsung devices
Open the Settings app
Tap Connections > SIM manager.
Choose your Smart SIM.
Under Preferred SIMs:
Set Calls: Select your Primary SIM.
Set Text messages: Select your Primary SIM.
Set Mobile data: Select your Primary SIM.
Toggle Data Switching to ON.
Go back and tap Mobile networks > Roaming.
Toggle Data roaming to ON.
Xiaomi devices
Open Settings
Tap SIM cards & mobile networks.
Select your Smart SIM.
Under Default settings:
Set Calls: Select your Primary SIM.
Set Text messages: Select your Primary SIM.
Set Mobile data: Select your Primary SIM.
Enable Data roaming under the same menu.