The fastest way to lock individual apps depends on your phone type

If your phone runs Android 11 or later, you have a built-in app lock feature called App Lock (on Samsung phones) or App Locker (on other Android brands). On iPhones running iOS 17 or later, the feature is called App Lock and lives in Settings. Both let you require a fingerprint, face scan, or PIN before someone can open a specific app — without locking your entire phone.

The setup takes about two minutes per app. You don't need to read anything extra if your phone is recent enough. If your phone is older or you want more control over which apps lock and how, third-party apps like Applock (by DoMobile) or Norton App Lock offer alternatives, though they require you to trust another company with access to your phone's security layer.

Key Takeaways

  • Android 11+ and iOS 17+ both have free, built-in app locks that require a fingerprint, face scan, or PIN before opening a specific app.
  • You set up app lock separately for each app you want to protect — your email, banking app, photos, or messaging apps are common choices.
  • If someone knows your phone's unlock code, they can still access your app lock settings and turn off protection, so app lock is not a substitute for a strong phone password.
  • Third-party app lock apps exist but add a security risk: you are giving another company permission to monitor which apps you open.
  • App lock works best for protecting against casual snooping by family members or coworkers, not against someone determined to break into your phone.

How to set up app lock on Android (Samsung and other brands)

On Samsung phones, open Settings, then tap Biometrics and security (or Security on older models). Look for App Lock or find Folder. Tap it, then tap the plus sign or Add apps. Select each app you want to lock — Gmail, your banking app, Photos, Messages, whatever you use most. Once you add an app, the phone will ask you to set your unlock method: fingerprint, face recognition, or a PIN.

On non-Samsung Android phones (Google Pixel, OnePlus, Motorola, etc.), the path varies slightly. Open Settings, search for App Locker or App Lock, and follow the same steps. If you don't find it, your phone may be running Android 10 or earlier, in which case you'll need a third-party app or to upgrade your phone.

Once you've added apps, test the lock by closing the app completely and reopening it. You should see a prompt for your fingerprint, face, or PIN before the app opens. If you don't see the prompt, go back into App Lock settings and make sure the toggle next to that app is turned on.

How to set up app lock on iPhone (iOS 17 and later)

Open Settings and scroll down to find Apps. Tap App Lock. You'll see a toggle to turn App Lock on; switch it to on. Then tap Add apps and select the apps you want to protect. iPhone will ask you to confirm with Face ID, Touch ID, or a passcode — use whichever method you prefer.

Unlike Android, iPhone's App Lock is all-or-nothing for the unlock method: you can't use Face ID for one app and a PIN for another. All locked apps on your iPhone will use the same unlock method. If you want different apps to use different protections, you'll need a third-party app, though this is rarely necessary.

Test the lock the same way: close the app and reopen it. You should see a Face ID, Touch ID, or passcode screen before the app opens.

What app lock does and doesn't protect

App lock stops someone from opening an app without your permission — useful if you share your phone with family, roommates, or coworkers. It does not protect your data if someone steals your phone and has time to crack your main phone password. Once they unlock your phone, they can go into Settings, turn off app lock, and read everything inside.

App lock also doesn't encrypt the data inside the app. If someone gains access to your phone's files through a computer or a backup, they may be able to read your app data even if the app itself is locked. For truly sensitive information — banking passwords, health records, private messages — app lock is a first layer, not the whole solution.

App lock works best against quick, casual access: a family member picking up your phone to check the time, a coworker glancing at your screen, or a friend trying to snoop through your messages. It is not a defense against someone with technical skill or physical access to your phone for an extended period.

When to use third-party app lock apps

Third-party apps like Applock, Norton App Lock, or Smart AppLock add features that built-in app locks don't have: the ability to lock apps with different passwords, hide apps from your home screen, or take a photo if someone enters the wrong password too many times. Some people prefer these options, especially if they share a phone with multiple family members who need different access levels.

The trade-off is trust. When you install a third-party app lock, you are giving that company permission to monitor which apps you open, when you open them, and how often. You are also adding another layer of software that could have its own security flaws. Before installing a third-party app lock, read the reviews on your phone's app store and check the company's privacy policy to see what data they collect.

For most people, the built-in app lock on Android 11+ or iOS 17+ is sufficient. Third-party apps are worth considering only if you need features the built-in version doesn't offer, or if your phone is too old to have a built-in app lock.

What to do if you forget your app lock password or fingerprint

If you forget the PIN you set for app lock, you can reset it by going back into App Lock settings and tapping Change unlock method or Reset. You'll need to unlock your phone first (using your main phone password), then you can set a new app lock PIN. This is why a strong main phone password is critical: if someone knows it, they can disable app lock entirely.

If your fingerprint or face recognition stops working with app lock, go into the app lock settings and re-register your fingerprint or face. Your phone may ask you to re-scan your finger or face a few times to improve accuracy. If the problem persists, you can switch to a PIN as a backup unlock method.

Common mistakes that weaken app lock protection

Using the same PIN for app lock as your main phone password defeats the purpose. If someone guesses your phone password, they can also access your app lock settings. Use a different PIN for app lock — something you can remember but that isn't obvious (not your birthday or a straightforward sequence like 1234).

Leaving app lock settings visible on your home screen makes it straightforward for someone to find and disable it. Keep Settings in a folder or at the bottom of your home screen so it's not the first thing someone sees when they pick up your phone.

Assuming app lock is enough security is the biggest mistake. App lock is one layer. You still need a strong main phone password, you should turn on automatic lock (so your phone locks after a few minutes of inactivity), and you should keep your phone's software updated. Each of these alone is weak; together they create a real barrier.

Frequently Asked Questions

Can someone turn off app lock if they know my phone password?

Yes. App lock settings live inside your phone's main settings, so anyone who can unlock your phone can go into App Lock and turn it off. This is why your main phone password needs to be strong and unique. App lock protects against casual snooping, not against someone with full access to your phone.

Does app lock work if my phone is stolen?

Only if the thief doesn't know your main phone password. If they crack your phone password, they can disable app lock. If your phone is stolen, your best protection is to use your phone's remote lock feature (Find My iPhone for Apple, Find My Mobile for Samsung) to lock or erase it before the thief has time to try passwords.

Can I use app lock on apps that don't support it?

No. Built-in app lock only works on apps installed from your phone's app store. Web apps, browser bookmarks, and sideloaded apps can't be locked with the built-in feature. Third-party app lock apps sometimes claim to lock more apps, but their success varies.

Will app lock slow down my phone?

No. Built-in app lock uses your phone's existing security hardware (fingerprint sensor, face camera) and adds almost no processing load. Third-party app lock apps may use slightly more battery and storage, but the difference is usually not noticeable.

What's the difference between app lock and hiding an app?

App lock requires authentication to open an app that's visible on your home screen. Hiding an app removes it from your home screen entirely, so someone has to search for it or dig through your app library to find it. You can use both together for extra privacy, but hiding alone is not as find as locking because someone can still find the app if they look.