Could Mobile Phones be Tracked by IMSI Catcher when there is No Cellular Signal?

Could a mobile phone be tracked by an IMSI catcher when there is no telecom service, or no cell phone signal?

The answer is yes, only if there is a SIM card inside the phone.

In some remote areas, such as mountains or forests, telecom service might not be available. So even if you have a SIM card inserted in your phone, there would be no signal bars. And you would not be able to reach out to anybody else by a phone call or through internet.

Then, the question is, how could it be detected by an IMSI catcher? Let’s have a look at the definition of IMSI catcher first.

IMSI catcher, also known as cell-site simulator, or Stingray, is a surveillance tool that masquerades as legitimate cell-phone towers, tricking phones within a certain radius into connecting to the device rather than a tower.

Now the reason should be clear. When there is no telecom service in the environment, i.e., there are no base stations nearby to provide telecom service, an IMSI catcher can act as the base station which your smart phone can establish connection to. And this is the reason why IMSI catcher is an effective tool to search and rescue people in mountain and forest areas, where it’s quite likely that telecom service is not available. Even if telecom service is there, IMSI catcher, especially those mounted on a drone, could still act as an ideal tool for search and rescue because it can efficiently detect and locate the targets. Search and rescue in earthquake are also a scenario where IMSI catcher could play an important role, as telecom infrastructure is usually destroyed by the power of earthquake and thus telecom service is interrupted.