If the Police have your mobile phone number then I understand they can track your mobile phone. Now, I understand the mobile phone number is linked to the sim card but if you simply change the sim card does that stop the Police from tracking you? Because I also understand that all mobile phones have a IMEI number.

Can the fact they had the sim card mobile number while inserted into a mobile phone give them access to that number so even if you change the sim card, they can track the mobile phone no matter what sim card is inserted? Hence, if so, is a new mobile phone and sim card is the only option ?

2 Answers 2


It depends on the method you are being tracked. If we are talking about a "wiretap," then the tracking is being done at the telco and as long as you maintain the same phone number, regardless of SIM or phone, it will get captured. If we are talking about false mobile towers, like Stingray devices, then you are being tracked by multiple factors; SIM, phone number, IMEI, etc.

  • Hi, Shackledtodesk, I am assuming they are not tracking the phone all the time, But might be looking back at movements and when perhaps I hit towers in a certain city, I am not sure if they can do this, But I would imagine they can with a known number as they have done this with missing persons, I am guessing they triangulate position from signal strength at towers and using timeline can tell what road your on and where you stopped, But from what tracking methods you say they can use, Is a PAYG mobile phone with new number is the method that will definitely defeat them ? Oct 25, 2016 at 0:39

I don't know the technical details to answer your specific question, but it might not be relevant.

If your phone has been tracked in the past and you live in a place where your adversary has access to cell phone location data, and you do get both a new phone and a new phone number, your new "mobile phone identity" can be easily connected to your old one if you don't also change your behaviour radically. If you keep your new phone on for the same periods of time, move around in the same patterns etc, it should be fairly easy to connect the two profiles simply by matching movement patterns. In fact, depending on how accurate cell tower localization is and where you live, simply going to work and coming home every day is probably enough to connect your new phone and phone number to you/your old phone and phone number.

  • Your answer assumes that the adversary "suspects" a new phone already. Given the number of people that live in the given area who all own mobile phones, it would be incredibly difficult to data-mine all the phones and their locations at once.
    – Luke Park
    Oct 23, 2016 at 1:16
  • If you're being tracked by a police-state adversary and you stop using your old phone, it seems likely that your adversary realizes fairly quickly that you've changed your phone. After all, this isn't such a special event; we all upgrade our phones and change our carriers now and then. And no, taking all available phone records and calculating a fuzzy fingerprint consisting of the two locations the phone is most often at is hardly difficult for a state-level adversary. You're right that this isn't exact, but it might be good enough. I'm not saying anybody does that, just that it's feasible. Oct 23, 2016 at 15:07
  • They cant track my mobile phone by regular movements as its infrequently moved and used, And they must know by now it`s been abandoned, The PC ( Daniel, in Exeter, Devon ) Said I had to give him my mobile number, I heard from several films and TV Shows that my name and address is all I have to give, But I thought no matter the second you have that number the mobile phone and sim is going in the bin, The real question is about if they can trace a new mobile phone by temporary putting a known sim in a new mobile phone and that gives them the new phones IMEI number Nov 21, 2016 at 18:14
  • If your phone is infrequently moved and used, that is also a pattern. We know the NSA looks for patterns. The GCHQ might, too. The british police probably doesn't, as Britain isn't a police state. Nov 21, 2016 at 18:46
  • 1
    @Pascal Especially given the Investigatory Powers Act ("Snooper's Charter"), some people may disagree with you on that.
    – user
    Dec 5, 2016 at 16:04

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