How to block ad tracking on your iPhone

In 2019, an article in The Washington Post by Geoffrey Fowler described the author’s shock when he discovered how many of his iPhone apps were collecting and uploading information about his use while he slept.

As we all now know, data is a big commodity these days. If you use a phone, laptop, or any type of computer device (unless you are a security expert or an excellent hacker with access to sophisticated blocking tools), you pay for your programs by contributing marketing and other information to the companies they provide.

As Fowler’s article shows, iPhone users are not immune to this. Since its article was published, Apple has made some commendable changes to its privacy policy. But it’s still a good idea to control your own data. There are some simple ways to limit the amount of tracking that app vendors can do, and the amount of data they have access to.

Eliminate personalized and location-based ads

According to Apple’s Advertising and Privacy Page:

Apple’s advertising platform does not track you, which means that it does not link user or device data collected from our applications to user or device data collected from third parties for targeted advertising or ad measurement purposes, and not user or device data do not share with data brokers.

However, the page further states that contextual data, such as information about your device, its location, your App Store searches, and what you read on Apple News, may be collected. You can bypass this somewhat by eliminating personalized and location-based ads.

To turn off personalized ads

• Select your “Settings” app, tap “Privacy” and scroll down and select “Apple Advertising” (this will be near the bottom of the list).
• Disable “Personalized Advertising”.

To turn off location-based ads

• Select “Settings”> “Privacy”> “Location Services” (top of screen).
• Disable Location Services.

On this page, you can also change several of your apps, such as the App Store or Maps, to never allow access to the location, ask the next time or when you use the app. Also note that you can still use the “Find My Phone” feature; it will temporarily turn on Location Services.

If you want to see how effectively your phone is protected, you can take the Panopticlick test, presented by the Electronic Frontier Foundation. It monitors, among other things, devices’ fingerprints. I used it on an Apple iPhone 11 after following the instructions above, and I got a ‘partial protection’ for blocking tracking ads, blocking invisible trackers and fingerprint protection.

Quit Safari

If you use the Safari browser on your iPhone, you can do several things to make it more secure.

• Go to “Settings”.
• Select “Safari” and browse to the “Privacy and Security” section.
• Enable ‘Prevent Website Tracking’ (meaning that third-party advertisers and other content providers will not be able to track you from one website to another).
• Turn on ‘Block all cookies’. The cookies collected by different websites can contain a lot of information about how you use the website, what information you put in it, etc. By blocking cookies, you prevent the data from being collected.

However, you will probably make things very inconvenient for you. Your visits to websites will not be recorded. For example, you can not revisit a playlist or buy back the same T-shirt you bought last year. Some sites will even deny access if you do not allow cookies to be collected. It’s your choice.

Disable background application reload

According to Apple, the reason Background App Refresh has been turned on is to allow suspended applications (applications that are not currently active) to check for updates and new content. According to Disconnect, the privacy app company that Geoffrey Fowler mentions in his article, it also allows apps to collect and transmit marketable tracking data, even if you are not using the app. Interestingly, iPhones are shipped with Background App Refresh enabled, but it is not very difficult to disable.

• Go to “Settings”.
• Select ‘General’.
• Select “Refresh Background Program.”
• You will see a list of all the programs that use this feature, and they will all be turned on. Find ‘Background app refresh’ at the top of the page and tap on it.
• You will be taken to a page that allows you to enable it for Wi-Fi and mobile data, for Wi-Fi only, or you can turn it off completely. Select ‘Off’.
• If you go back to the previous page, you will see that all the switches for the different programs are completely gone.

You may want to be picky about which programs can work in the background. Some programs may not work well. For example, Google Photos does not automatically back up your camera roll unless this feature is enabled. So you can, if you want, enable “Background App Refresh” and then choose which specific apps you want to disable.

Update 8 March 2021, 17:00 ET: This article was originally published on May 30, 2018; several sections have been updated to reflect changes in iOS.