Deactivate your SIM card if you are traveling with a group

You should not use it to make calls, send text messages or use your mobile internet connection. Remove it from your phone to be on the safe side. If you move through identical cells with other people over a longer period of time, it is theoretically possible to narrow down who you could be or who your family or friends are. The same applies to a possible second SIM card registered in your name. For example, if you have a second non-anonymous phone with you. If this SIM card moves through an area together with the anonymous SIM card, it is known who the anonymous card belongs to based on the same cell changes. The cell changes may be logged in your provider's traffic data. Have friends provide you with a Wi-Fi hotspot when you are traveling and use it with a VPN or Tor. If you are traveling with a larger group, only one person should create a hotspot. Everyone else should remove their SIM cards for this time.