How to Block No Caller ID Calls on iPhone and Android

You can stop hidden-number calls on both platforms, but the tools work differently. Android has a setting that blocks only calls with no caller ID. iPhone does not: its option silences everyone who isn't already in your contacts or recent calls, and hidden numbers are part of that group. The steps for each phone are below, along with the calls you could lose by switching them on.

Block No Caller ID on iPhone

Apple moved this setting in iOS 18 and changed it again in iOS 26. Use the path that matches your phone's version (Settings > General > About > iOS Version).

iOS 26: Screen Unknown Callers

1. Open Settings, tap Apps, then Phone.
2. Tap Screen Unknown Callers.
3. Pick one of three options:
   • Silence: unknown callers, including No Caller ID, go straight to voicemail without ringing.
   • Ask Reason for Calling: your iPhone picks up, asks the caller for their name and reason, and shows you a transcript before it rings. Robocalls usually hang up at this point.
   • Never: everything rings as normal.

Ask Reason for Calling is the better choice for most people (how iOS 26 call screening works). A hidden-number caller with a real reason, like a clinic or a courier, can say so, and you decide whether to answer.

iOS 18

Settings > Apps > Phone > Silence Unknown Callers, then turn it on.

iOS 17 and older

Settings > Phone > Silence Unknown Callers, then turn it on.

What "unknown" means to an iPhone

Calls still ring from numbers that are in your Contacts, numbers you recently called, and numbers Siri Suggestions has found in your Mail or Messages. Everything else is silenced, logged in Recents and sent to voicemail. That includes hidden numbers, as well as any genuine caller you've never saved.

Block No Caller ID on Android

On Android you can block just the hidden numbers and leave calls from unsaved numbers alone. Menu names vary a little by manufacturer and Android version.

Google Pixel and other phones using the Google Phone app

1. Open the Phone app.
2. Tap the three-dot menu, then Settings.
3. Tap Blocked numbers.
4. Turn on Unknown.

Google's help page says this blocks private or unidentified callers, and calls from numbers that aren't in your contacts still ring. On Pixel phones in supported countries, Call Screen (Phone settings > Spam and Call Screen) can also answer unknown callers for you, much like the iOS 26 option.

Samsung Galaxy

1. Open the Phone app.
2. Tap the three-dot menu, then Settings.
3. Tap Block numbers.
4. Turn on Block unknown/private numbers (older One UI versions call it "Block unknown callers").

Samsung's toggle covers hidden and unidentified numbers only (Samsung support). It doesn't block a normal number just because you haven't saved it.

Quick comparison

Landlines: Anonymous Call Rejection

Many US landline providers offer Anonymous Call Rejection. You switch it on by dialling *77 from the home phone and off with *87. A caller who withheld their number hears a message telling them to unhide it and call again. Coverage and charges vary by provider (AT&T's description). Calls marked "Unavailable" or "Out of area" can still get through, and the code is for landlines only, so don't dial it from a mobile.

Calls you might lose

Blocking hidden numbers cuts out a lot of junk, but some genuine callers withhold their numbers by default:

• Hospitals, GP surgeries and clinics, which often call from internal lines that show as private.
• Police and social services.
• Some banks' fraud teams, although many now call from a published number.
• Relatives overseas. International calls sometimes show up as "Unknown" or with an unfamiliar number, because a carrier along the route dropped or changed the caller ID. Our explainer on Unknown Caller vs No Caller ID covers why this happens.

If you're expecting one of these calls, switch to the screening option (iOS 26 Ask Reason, or Pixel Call Screen) for that week rather than blocking outright, and check voicemail.

When you're the one getting blocked

The same settings work against you when you call someone abroad. If your parents have Silence Unknown Callers on and your call arrives from an unfamiliar number, their phone won't ring.

The fix is to call from a number they already have saved. With EzyRing you can do that from a browser. You verify a number you own once (we call it and you key in a code), and your calls go out with that number as the caller ID. Most cross-border calls show it, but the recipient's carrier decides in the end. Some countries withhold or replace a domestic-looking number that arrives from abroad, and the verified caller ID page explains those limits. Before you call, check the per-minute rate for the country.

Related reading

• How to find out who a No Caller ID is
• How to hide your caller ID on iPhone