Every time you open an app, your phone may be broadcasting your exact physical location to advertisers. Location-based advertising is a multi-billion-dollar industry built on tracking where you go — and that data is far more revealing than most people realize. A record of your movements can expose where you work, where your kids go to school, which doctors you visit, and which places of worship you attend. This guide explains how location-based advertising works and walks you through every setting you need to change on iPhone and Android to shut it down.
How Location-Based Advertising Works
Advertisers use your physical location to serve you targeted ads — a coffee shop ad when you walk past a competitor, a car dealership promotion when you visit an auto lot, or a political ad based on your neighborhood. They rely on several technologies working together:
- GPS: The most precise method, accurate to within a few meters. Apps with location permission can read your GPS coordinates directly.
- Wi-Fi triangulation: Your phone scans for nearby access points even when not connected. Matching those against a known database estimates your position within 15–30 meters.
- Bluetooth beacons: Small transmitters placed in retail stores, malls, airports, and stadiums. When your phone detects a beacon, the associated app knows which aisle or gate you are near.
- Cell tower data: Your phone constantly connects to nearby cell towers. Cell tower triangulation can place you within a few hundred meters — enough to identify your neighborhood or shopping center.
- IP geolocation: Websites and apps estimate your approximate location from your IP address, typically accurate to the city or ZIP code level.
How Your Location Data Gets Sold
When you grant an app location permission, the app’s SDK (software development kit) may quietly send your coordinates to a data broker — often dozens of times per day. The app developer gets paid for each user’s data, and the broker aggregates millions of users into a dataset that advertisers can query.
The worst offenders for location harvesting
Weather apps, flashlight apps, free games, and photo-editing apps are consistently the worst offenders for collecting and selling location data. Many of these apps have no legitimate reason to know your location, but they request the permission anyway because selling your GPS coordinates to data brokers is their actual business model. If an app is free and asks for your location without an obvious reason, your location data is likely the product.
This data doesn’t stay with one company. It flows through a chain of brokers, aggregators, and ad-tech platforms — bought and sold multiple times, combined with other data points, and used to build a detailed profile of your movements.
Major Location Data Brokers
Several companies specialize in collecting and selling location data at scale:
- Foursquare / Factual: One of the largest location data companies, powering location intelligence for major brands. Foursquare acquired Factual in 2020 and processes billions of location signals daily.
- Placer.ai: Provides foot-traffic analytics to retailers, real estate firms, and hedge funds — tracking how many people visit a store, how long they stay, and where they go next.
- Near (formerly X-Mode Social): Collected location data from apps including Muslim prayer apps and dating apps. The FTC took enforcement action for selling sensitive location data without adequate consent.
- SafeGraph: Aggregates location data from mobile apps to track foot traffic to businesses, hospitals, and points of interest. Faced criticism for selling data that could track visitors to abortion clinics.
The FTC’s Crackdown on Location Data Brokers
The Federal Trade Commission has started taking action against location data brokers that collect and sell sensitive location information:
- X-Mode Social / Outlogic settlement (2024): The FTC banned X-Mode (now Outlogic) from selling sensitive location data that could reveal visits to medical facilities, religious organizations, and domestic violence shelters — the first enforcement action against a location data broker.
- InMarket settlement (2024): The FTC ordered InMarket to stop selling precise location data for advertising without informed consent. InMarket had tracked consumers through its own apps and SDKs embedded in third-party apps.
These settlements signal that the FTC views the sale of precise location data as a serious privacy violation, but enforcement remains limited. Most location data brokers still operate freely, which is why you need to cut off the data at the source.
How to Opt Out on iPhone
Apple provides strong location privacy controls, but most are not set to the most protective option by default.
Review App Location Permissions
Go to Settings > Privacy & Security > Location Services and review every app in the list. For each app:
- Set the permission to Never for any app that does not genuinely need your location.
- Set the permission to While Using the App instead of Always for apps like maps or ride-sharing that need location only when you are actively using them. The “Always” setting lets apps track your location in the background 24/7.
- Turn off Precise Location for apps that work fine with an approximate location, such as weather and news apps.
Block All App Tracking
Go to Settings > Privacy & Security > Tracking and turn off Allow Apps to Request to Track. This prevents apps from tracking your activity across other companies’ apps and websites — a primary mechanism for linking location data to your ad profile.
Disable Apple’s Personalized Ads
Go to Settings > Privacy & Security > Apple Advertising and turn off Personalized Ads. This stops Apple from using your data to target ads in the App Store, Apple News, and Stocks.
Check System Services too
In Settings > Privacy & Security > Location Services, scroll to the bottom and tap System Services. Turn off Location-Based Apple Ads, Location-Based Suggestions, and Significant Locations. Tap Clear History under Significant Locations to delete Apple’s log of places you visit frequently.
Skip the manual opt-outs
One opt-out won't stop them — brokers relist your data. PrivacyOn removes your info from 100+ sites and keeps it removed.
Start your free scanHow to Opt Out on Android
Google’s ad-driven business model means Android requires more settings changes across more places.
Review App Location Permissions
Go to Settings > Location and tap App location permissions. Review every app and change “Allowed all the time” to Allowed only while using the app or Not allowed. Under Location Services, turn off Wi-Fi scanning and Bluetooth scanning to prevent location detection even when those radios are turned off.
Delete Your Advertising ID
Go to Settings > Privacy > Ads and tap Delete advertising ID. This removes the unique identifier advertisers use to link your app activity to your location data. On older Android versions, reset the ID and turn off ad personalization instead.
Turn Off Google Ad Personalization
Open your Google Account > Data & Privacy > Ad Settings and turn off Ad personalization. This prevents Google from using your search history, YouTube activity, and location data to target ads across its network.
Disable Google Location History / Timeline
Google Location History (now called Timeline) records everywhere you go, even when you are not using Google Maps. Go to Settings > Location > Location Services > Google Location History and turn it off. Visit timeline.google.com to delete your existing history. Also go to Google Account > Data & Privacy > Activity Controls and pause Web & App Activity.
Browser-Level Protections
Websites can also request your location through your browser. Deny these requests to force sites to fall back on IP geolocation, which is far less precise (city-level rather than street-level):
- Safari: Settings > Apps > Safari > Location — set to Deny or Ask.
- Chrome (desktop): Settings > Privacy and Security > Site Settings > Location — set to Don’t allow.
- Chrome (mobile): Three-dot menu > Settings > Site Settings > Location — toggle off.
- Firefox: Settings > Privacy & Security > Permissions > Location — check Block new requests.
How Data Brokers Build Location Profiles
Individual location pings seem harmless, but aggregated over weeks they become deeply revealing. Data brokers combine your location signals to determine:
- Your home address (where your phone spends the night)
- Your workplace (where your phone sits for eight hours on weekdays)
- Your daily commute route
- The stores, restaurants, gyms, and doctors you visit regularly
- Your political leanings (based on rally attendance or neighborhood demographics)
- Your religious affiliation (based on house of worship visits)
This profile is sold to advertisers, hedge funds, insurance companies, law enforcement, and anyone else willing to pay. Studies have shown that “anonymized” location data can be re-identified with startling accuracy — just four data points are often enough to uniquely identify a person.
Let PrivacyOn Handle the Data Brokers
Changing your phone settings stops new location data collection, but it does not erase data already collected and sold. Your location history may already sit in dozens of broker databases. PrivacyOn removes your personal information from 100+ data broker sites — including location data aggregators — by submitting opt-out requests on your behalf, tracking their completion, and monitoring for re-listings so your location data stops following you around the internet.