Here are the 10 ways to tell whether or not someone is monitoring your smartphone.

1) Unusually High Data Usage

Has your monthly data usage spiked recently? Is your device using more data than normal, yet you haven’t changed your online habits? That could indicate that someone has installed spyware on your device.

Lower-quality spy tools will try to send as much data about your device back to their home base (AKA the bad guys) as they possibly can. This can use large amounts of data.

On the other end of the spectrum, some of the spyware makers are quite skilled at it, and their sneaky apps are much more selective with what info they look for and send back home. This makes detection a bit tougher. 

It all comes down to making sure that you stay aware of your monthly data usage and pay close attention to any sudden spikes in usage that you might see.

While you can contact your wireless carrier to check on how much data you’ve used, you can also check on your device. This means you can quickly check data usage without the need to search around on your provider’s website or app for data usage information.

How to Check Cellular Data Usage on Android

To check your cellular data usage on an Android 9 device, do the following. (The process should be similar on other versions of Android.):

1. Open the Android Settings app.
2. Tap “Mobile Network” (It’s in the “Network & Internet” section.)
3. On the Mobile Network screen, tap “App Data Usage.”
4. Here, you can view your current cellular app data usage. (You can select other date ranges for viewing.)

How to Check Cellular Data Usage on an iPhone

To check your cellular data usage on an iPhone running iOS 14, do the following. (The process should be similar on other versions of iOS and on iPads running iPadOS.):

1. Open the iOS 14 Settings app.
2. Tap the “Cellular” menu option.
3. In the Cellular menu, tap the “Usage” menu option.
4. On the Usage screen, you can view the data usage for the current month.

2) Cell Phone Shows Signs of Activity in Standby Mode

While you should expect your iPhone or Android phone screen to light up when you receive an incoming call, message or most other types of notifications, your smartphone’s screen shouldn’t be lighting up for no reason while it’s in standby mode.

If you see your device’s screen light up, hear unexpected noises or sounds and then you don’t see any new notifications on the screen, something could be up.

3) Unexpected Reboots

Is your smartphone rebooting for no obvious reason or without your manually rebooting it? Someone may have unauthorized remote access to your smartphone. 

Unexpected reboots may indicate someone has remote admin access and can reboot your device at will. This would also indicate they have all sorts of other access to your device and the personal data stored on it.

Or, it could mean the latest app or operating system you recently downloaded has a bug in it. Check for new updates for the OS or app. See if you can duplicate the device reboot by using the app that was open when it happened.

On your Android device, you can install and run antivirus or anti-malware security software to scan your device. iOS users will find that antivirus scanners are not available, and in the sandboxed iOS operating system, it’s more likely that there is a bug in an app or in the OS that is causing the reboots.

4) Odd Sounds During Calls

In the days of analog cell phone networks, weird noises in the background and unstable connections were to be expected. However, today’s all-digital cell networks usually provide connections that are stable and mostly noise-free.

So, if you are hearing weird noises in the background, or (even worse) hear a voice that doesn’t belong to the person you called, there is a possibility that someone is monitoring or recording your conversation. 

5) Unexpected Text Messages

Have you either received unexpected messages with weird characters in them or have your friends or other parties reported receiving weird or offensive messages from your phone?

This can be a sign that you have spyware or malware installed on your smartphone. SMS worms spread themselves through the online world by sending text messages with links embedded in them. If the victim taps the link, the worm can infect their smartphone.

On your Android device, you can install and run security software such as antivirus or anti-malware to scan your device. iOS users will likely not have to worry about these types of worms, as they target Android devices for the most part.

6) Deteriorating Battery Life

If you see your device’s battery life begin deteriorating rapidly and unexpectedly, that could mean your battery is old and in need of replacement. Or, it could mean that your device is infected with spyware, and the additional load it’s putting on your smartphone is draining the battery quicker than usual.

Spyware monitors all of your on-device activities and sends information about these activities back to the bad actors that infected your device. Shortened battery life often goes hand-in-hand with increased data usage due to the activities of the spyware. 

Taking screenshots, copying and pasting text, recording your conversations, and possibly taking photos or recording video can eat up battery life at an alarming rate. This is especially obvious when your smartphone is supposedly idle.

If you’re not sure whether it’s just an old battery or actual spy software, test this by trying a different set of batteries or trying your device’s battery in a different device. Then, monitor the battery usage. 

Sorry iPhone users, your device’s batteries are not removable. But, you can make a Genius Bar appointment and they can check your battery for you. iOS 14 users can take advantage of a new privacy feature that alerts you when an app on your device is using its camera or microphone.

If an app is using your iPhone’s camera, you’ll see an indicator light up at the top of your device’s screen, as shown here:

If an app is using your iPhone’s built-in microphone, you’ll see an indicator light up at the top of your device’s screen, as shown here:

While it is perfectly normal to see either of these indicators light up when apps are using either the camera or the mic, seeing them light up when you’re not actively recording video or audio should serve as a warning sign that something might be up.

Determining Which Apps Have Access to Your Device’s Microphone or Camera

It’s easy to check your device to find out which apps currently have access to your device’s microphone or camera. 

On the iPhone, do the following:

1. 1. Open the Settings app.
   2. Tap “Privacy” in the Settings app.
   3. Tap either “Microphone” or “Camera” in the privacy menu.
   4. On the next page, you can view which apps have access to the selected feature. You can also toggle the access on or off in this menu.

On an Android (9) Device, do the following:

1. 1. Go to the Settings app.
   2. Tap “Apps & notifications.”
   3. Tap “App permissions.”
   4. Tap “Camera” or “Microphone.”
   5. Here, you can view which apps have access to the selected feature. You can also toggle the access on or off in this menu.

7) Increasing Battery Temperature in Idle Mode

While increased battery temperature can be a sign of multiple technical issues, it can also indicate that unauthorized activities, like spyware activities, are occurring in the background.

If you haven’t used your smartphone recently, and it’s just been sitting idle on your desk, it shouldn’t be warm or hot to the touch. If it is overly warm, then spyware could be working behind the scenes, collecting information and sending it back to home base.

8) Increased Device Shut Down Time

Your smartphone, much like a Mac or Windows PC, attempts to shut down all active processes before turning itself off or when it is rebooted.

And, much like your computer, occasionally those processes can hang up and either prevent or greatly slow the shutdown process. While this can happen to any device, you may notice that it is happening more often than usual if your device has been infected with spyware.

You may notice that your smartphone takes longer than usual to shut down right after you’ve finished an active period with your mobile phone. This could mean the spyware is working in the background, saving its ill-gotten information and sending it back to home base. 

9) ​Difficulty in Shutting Down or Rebooting Your Device

In addition to slowing the shutdown process of your smartphone, spyware can also prevent your device from shutting down or rebooting completely.

Again, this can be caused by a harmless app misbehaving, but if it just started happening recently, or is happening more often than not, your device might be infected with spyware. (Did anyone else hear Jeff Foxworthy say that last sentence in their head? Just me? Okay.)

10) Your Cell Phone is Growing Increasingly Slower

High-end smartphones made in the last five years or so should run fast and not show many performance issues during day-to-day use. If you notice your smartphone is lagging, performing much worse than usual, or is suddenly running out of resources like memory or storage space, it might be infected with spyware.

This is tougher to tell with older smartphones or low-priced budget handsets like you get off the rack at Walgreens. But, if you pay attention to how your smartphone usually performs, you can usually tell if something is going on.

How to Find and Remove Spy Software on Your Smartphone

As mentioned above, there is no lack of spying apps available for smartphones. A few popular examples are:

1. Spyera
2. TheOneSpy
3. FlexiSPY
4. mSpy
5. Highster Mobile

All the spyware listed above can monitor and record text messages and phone conversations.

With these monitoring apps, a bad guy can take control of your mobile phone’s microphone and listen to everything that happens in your immediate surroundings or even records your phone calls.

Furthermore, the more advanced applications can even steal your passwords, use your camera to physically spy on you, or even lock your cell phone completely so you can’t use it anymore.