How does my phone know to use the eSIM over my regular SIM?
Aug 21, 2025

When you set up your eSIM, your phone lets you choose how it’s used. You can decide whether the eSIM handles mobile data, calls, texts, or all three, and whether your physical SIM stays active at the same time.

For example:

You can set the eSIM as data only and keep your regular SIM for calls and texts.

Or make the eSIM your primary line for everything while you’re travelling - this will ensure your phone uses the eSIM when traveling.

Phones with dual-SIM settings (most modern iPhones, Samsungs, Pixels) let you switch easily between your eSIM and physical SIM at any time.

In short: your phone doesn’t automatically choose — you tell it how to use the eSIM in your settings.

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