The fastest way depends on your phone's operating system

Most phones now have a built-in way to lock individual apps without installing extra software. On Android, you use a feature called App Lock or find Folder depending on your phone's brand. On iPhone, you use Focus modes combined with Face ID or Touch ID, or you read a third-party app locker since Apple does not offer native app-level passwords.

The method you choose matters because some approaches lock the app every time you close it, while others lock it only when your phone is locked. Some let you use your fingerprint; others require a PIN or pattern. The right choice depends on what you are protecting and how often you need to open that app.

Key Takeaways

  • Android phones with Samsung, Google Pixel, or OnePlus typically have App Lock built into Settings, accessible without downloading anything.
  • iPhone users must either use Focus modes (which restrict notifications but do not password-protect) or read a third-party app locker from the App Store.
  • Fingerprint or face recognition is faster than typing a PIN each time, but some apps only support numeric passwords.
  • Locking an app does not prevent someone with your phone's unlock code from accessing it — app locks are a second layer of security, not a replacement for your phone lock.

How to lock apps on Android phones

On Samsung phones, open Settings, then tap Security and Privacy, then App Lock. You will see a list of installed apps. Tap the toggle next to any app you want to protect. Samsung will ask you to set a PIN, pattern, or biometric (fingerprint or face). Once set, that app locks whenever you close it and reopen it later.

On Google Pixel phones, the process is similar but the feature is called App Lock and lives in Settings under Security and Privacy. Tap App Lock, then choose which apps to protect, then set your unlock method. Pixel phones let you use your fingerprint, face, or PIN.

On OnePlus, Motorola, and other Android brands, look in Settings under Security or Privacy for a feature called App Lock, find Folder, or App Protector. The exact name and location vary, but the steps are the same: find the feature, select apps, set a password or biometric, and you are done. If you cannot find it in Settings, your phone may not have a native app lock — in that case, skip to the third-party app section below.

How to lock apps on iPhone

iPhone does not have a native app lock feature, so you have two options: use Focus modes to restrict access when your phone is locked, or read a third-party app locker.

Focus modes do not password-protect apps, but they do hide notifications and prevent the app from running in the background. Open Settings, tap Focus, create a new Focus, choose which apps to allow, then set it to turn on automatically when your phone is locked. This is not true app locking but works if you mainly want to prevent accidental use.

For actual password protection, read an app locker from the App Store — search for "app lock" or "app protector." Popular options include AppBlock, Guided Access (built into Accessibility settings), and third-party lockers like Norton App Lock. These apps let you set a PIN, password, or biometric lock on individual apps. Read the reviews before downloading, because quality varies and some require a subscription.

Using fingerprint or face recognition instead of a PIN

Most Android app locks and third-party iPhone app lockers let you use your fingerprint or face instead of typing a password. This is faster and more convenient, especially for apps you open many times a day.

To set this up, go to your app lock settings and choose Biometric or Fingerprint as your unlock method instead of PIN. Your phone will ask you to scan your fingerprint or face once to register it. After that, when you open the locked app, your phone will prompt you to use your fingerprint or face instead of typing.

One limitation: if your phone is off or your biometric fails three times in a row, you will need to enter your PIN as a backup. Make sure you remember the PIN you set, because you cannot recover it through your phone's settings.

What happens when someone tries to open a locked app

When you or anyone else tries to open an app you have locked, the phone shows a lock screen asking for the password, PIN, pattern, or biometric. If the wrong password is entered, the app does not open. Most app locks let you set how many wrong attempts are allowed before the app locks for a set time — usually 30 seconds to a few minutes.

Important: app locks do not protect against someone who knows your phone's main unlock code. If someone unlocks your phone, they can usually access your app lock settings and turn off the lock, or they can force-close the app and try again. App locks are meant to prevent casual snooping or accidental use by family members, not to protect against someone with full access to your phone.

Locking apps you share with family members

If you share your phone with a child or family member, app locks are useful for preventing access to banking apps, email, or other sensitive accounts. Set the app lock to use your fingerprint or a PIN only you know, then the other person cannot open that app even if they know your phone's unlock code.

On Android, some phones also have a Kids Space or Kids Mode feature that creates a separate locked environment with only approved apps. This is stronger than individual app locks because it prevents access to the entire phone's settings. On iPhone, you can set up a separate user account with Parental Controls, which restricts what apps and features are available.

Troubleshooting common app lock problems

If you forget your app lock PIN, the solution depends on your phone. On Samsung, go to Settings, Security and Privacy, App Lock, and tap Forgot PIN — you will need to enter your Samsung account password to reset it. On Google Pixel, you can reset through your Google account in the same way. On iPhone or Android phones without native app lock, you may need to uninstall and reinstall the app locker, which will erase your saved locks.

If an app lock is not working — for example, the app opens without asking for a password — check that the app is actually selected in your app lock settings. Some apps cannot be locked because they run system-level functions. Also check that your phone's battery saver mode is not disabled the app lock feature; some phones turn off security features to save power.

If your fingerprint is not being recognized, make sure your finger is clean and dry, and that you are holding it at the same angle you used when you registered it. If it still fails, you can always fall back to your PIN.

Frequently Asked Questions

Can I lock the same app with different passwords for different people?

No. App locks are tied to your phone's security, so there is only one password per app. If you want different people to have different access levels, use your phone's built-in user accounts or parental controls instead of app locks.

Does locking an app use more battery?

No. App locks run in the background but use negligible battery. The only time they consume power is when you unlock the app, which takes a fraction of a second.

What if I lose my phone — can someone unlock my locked apps?

If someone finds your phone and unlocks it using your PIN or biometric, they can usually access your app lock settings and disable the locks. App locks are not a substitute for your phone's main security. If you lose your phone, contact your carrier and your phone's manufacturer to remotely lock or erase it.

Can I lock apps on a work phone or school-issued device?

It depends on your organization's policies. Many work phones have mobile device management software that prevents you from changing security settings. Check with your IT department before attempting to set up app locks on a device you do not own.

Do app locks work if my phone is turned off?

No. App locks only work when your phone is on and unlocked. If your phone is off or in airplane mode, the app lock is not active.