Is cellular tracking possible without SIM

justcurious

I don't have / don't plan to use a sim in my GrapheneOS device.

By default, will it transmit over mobile networks if no sim is inserted? Can it be tracked (using mobile networks) if there is no sim card?

(I'll be using wifi to a separate 4g dongle, but that is a different issue)

kopolee11

justcurious

I have seen several common suggestions in the privacy community to mitigate [carrier tracking] which do not actually work:

Removing the SIM Card: The baseband modem will continue to contact the cell towers with its IMEI to prepare for emergency calls. In fact, this is how you are able to call 911 even when you do not have a SIM card inserted.

https://privsec.dev/posts/android/android-tips/#carrier-tracking

The solution to prevent cellular tracking is to use airplane mode.

matchboxbananasynergy

You still ping cell towers without a SIM card. You can easily confirm that because you're able to make emergency calls without a SIM card. If you don't want to connect to cell towers, use airplane mode.

https://grapheneos.org/faq#cellular-tracking

justcurious

Perfect - thanks! Great to see I can still use wifi and bluetooth with Aeroplane mode: On