How to Block Unknown Numbers on Android
Block each number
Open the Phone app. It's the phone receiver icon, usually displayed on the home screen.
If you use a Samsung Galaxy, move on to the next method.
Access recent calls section. The location of this section will vary depending on the device. If the Phone app doesn't immediately open the recent calls section, you'll have to look for the clock icon or the word "Recent" here.
Touch and hold the number you want to block to open the menu.
Tap Block/report spam (Block/report unknown numbers). This option will have a different name on each device, but generally the name is related to Block . The screen will display a confirmation message.
You may have to select Blacklist or Block list here.
Tap Block when asked to confirm. Thus, you will no longer receive calls from this number.
Block all unknown numbers on Samsung Galaxy
Open the Phone app. You'll find the app with the handset icon on your home screen, or you can swipe the screen up or down to open the app drawer and search for the app here.
Tap ⋮ in the top right corner of the screen to open a list of options.
Tap Settings in the drop-down list to open the Call Settings page.
Tap Block numbers in the "CALL SETTINGS" section of the page.
Tap the white "Block anonymous calls" slider. This slider will change color, indicating that the Samsung Galaxy will no longer receive calls from unknown numbers.
If you only want to block a number, enter the number in the "Add phone number" field near the top of the page and select Done on the keypad.
You can still receive calls from people who are not in your contacts as long as they are not using a fake phone number. If you want to block calls from people in your contacts, try using the "Should I Answer?" app.
Block all unknown numbers on Android devices
Download the app "Should I Answer?" . This is an application that reviews incoming calls and can be set to block all incoming calls (including numbers that are not in your contacts). To download the application, open the Play Store , then do the following:
Tap the search bar.
Typeshould I answer
Tap Should I Answer?
Touch INSTALL (Install)
Tap ACCEPT (Accept)
Open the Should I Answer app. Tap OPEN in the Google Play Store, or tap the app's octopus icon in the app drawer on Android.
Tap CONTINUE at the bottom of the screen.
Tap the SETTINGS tab at the top of the screen.
Scroll down to the "Block INCOMING Calls from" heading. It's near the middle of the Settings page.
Turn on incoming call blocking. Tap the white slider to the right of any (or) all of the following conditions:
local negative rated numbers (local negative rated numbers)
community negative rated numbers (numbers rated negatively by the community)
numbers not stored in contacts (numbers not stored in contacts)
hidden numbers (hidden numbers)
foreign numbers (foreign numbers)
Block messages from unknown numbers if necessary. If you want to block messages sent from unknown/non-contact numbers, scroll down to the "Block INCOMING SMS" section and tap the white slider next to the option you want to apply.
Exit Should I Answer application to save settings. Now, calls from unknown numbers will be blocked.