To block calls with "No Caller ID," the options depend on the phone type:
- On iPhone: Use the built-in "Silence Unknown Callers" feature (Settings > Phone > Silence Unknown Callers). This sends calls from unknown numbers, including No Caller ID, directly to voicemail without ringing. Calls from contacts or Siri Suggestions will still ring. This does not block but silences such calls. Another trick is to create a fake contact named "No Caller ID" with a dummy number and block that contact, but its effectiveness is limited. Carriers may offer anonymous call blocking services as well.
- On Android: Most Android phones have a setting to block unknown or private numbers. This is usually found in the Phone app's Call Settings or Call Blocking rules. Enabling "Block unknown/private numbers" will stop No Caller ID calls from ringing. Some devices and carriers provide additional spam and anonymous call blocking options.
- Third-party call-blocking apps can also help by identifying and blocking spam and No Caller ID calls via community databases.
In summary, while you cannot block No Caller ID calls outright by number since the number is hidden, you can largely silence or filter them using phone settings or carrier services on both iPhone and Android devices.
