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Unknown callers

How to screen or block unknown callers

“Unknown caller” can mean different things depending on the phone. iPhone can screen or silence numbers that are not saved, while Google’s Android “Unknown” blocking setting specifically targets private or unidentified caller ID. That distinction matters if you still want legitimate first-time callers to reach you.

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Quick answer

Choose the least aggressive setting that solves your problem. Screening is often a better starting point than blocking every unfamiliar caller because doctors, schools, delivery drivers and businesses may call from numbers you have not saved.

Recommended protections

What to turn on

iPhone

Screen calls from unknown numbers

1 min

Makes unknown callers identify themselves before your iPhone rings, or sends them straight to voicemail if you choose Silence.

Keep in mind: Expected callers whose numbers are not saved may be delayed by screening. Silence can send legitimate first-time callers directly to voicemail.

Setup

  1. Open Settings on your iPhone.
  2. Tap Apps, then tap Phone.
  3. Open the setting for screening calls from unknown numbers.
  4. Choose Ask Reason for Calling for a balanced setup.
  5. If you want the most aggressive interruption reduction, choose Silence instead.
Official Apple guidance · Verified 2026-09-22
Android

Turn on caller ID and spam warnings

1 min

Shows warnings for suspected spam callers and identifies some callers or businesses that are not in your contacts.

Keep in mind: This identifies suspicious calls but does not automatically block them by itself.

Setup

  1. Open the Phone app.
  2. Tap More options, then Settings.
  3. Tap Caller ID and spam.
  4. Turn on See caller ID & spam.
Official Google guidance · Verified 2026-09-22
Android

Automatically filter spam calls

1 min

Automatically prevents many suspected spam calls from ringing your phone.

Keep in mind: With Filter spam calls, you may not receive missed-call or voicemail notifications for filtered calls, although calls remain in call history and voicemail can still be checked.

Setup

  1. Open the Phone app.
  2. Tap More options, then Settings.
  3. Open Caller ID and spam and turn on Filter spam calls if that option appears.
  4. If you use a Pixel and Filter spam calls is not shown, open Spam and Call Screen or Call Screen and enable automatic call screening.
Official Google guidance · Verified 2026-09-22
Android

Block private or unidentified callers

1 min

Automatically declines calls from numbers that do not provide caller ID.

Keep in mind: This can block legitimate callers who intentionally hide their number. It does not block ordinary unsaved numbers that still show caller ID.

Setup

  1. Open the Phone app.
  2. Tap More options, then Settings.
  3. Tap Blocked numbers.
  4. Turn on Unknown.
Official Google guidance · Verified 2026-09-22
AT&T

Turn on AT&T ActiveArmor spam-call blocking

2 min

Uses AT&T's network and ActiveArmor controls to block, label, or route suspected spam calls.

Keep in mind: AT&T says the service may inadvertently block wanted calls. Sending calls to voicemail requires an active voice mailbox.

Setup

  1. Download or open the AT&T ActiveArmor app and complete the activation prompts.
  2. Open the Calls tab.
  3. Under call routing, set Spam calls to Block or Send to voicemail.
  4. Leave Fraud calls set to Block.
  5. Turn on Always allow contacts so saved contacts are not blocked or routed to voicemail.
Official AT&T guidance · Verified 2026-09-22
T-Mobile

Turn on T-Mobile Scam Block

1 min

Blocks calls T-Mobile identifies as Scam Likely at the network level before they reach your phone.

Keep in mind: T-Mobile warns that Scam Block may block calls you want. You can disable it at any time.

Setup

  1. From your T-Mobile phone, dial #662# and press Call.
  2. Follow the confirmation message to verify Scam Block is enabled.
  3. Alternatively, open T-Life, go to Scam Shield, and turn on Scam Block.
Official T-Mobile guidance · Verified 2026-09-22
Verizon

Turn on Verizon Call Filter free spam protection

3 min

Detects suspected spam and automatically forwards high-risk spam calls to voicemail.

Keep in mind: Verizon says spam detection can mislabel or block legitimate callers. Add important numbers to Contacts or Allowed Numbers.

Setup

  1. Open Verizon Protect or the Call Filter app, depending on which app Verizon shows for your device.
  2. Open Call Filter and choose the free spam-protection option if setup is required.
  3. Confirm activation and keep the Spam Filter enabled. Verizon's default blocks high-risk spam by sending it to voicemail.
  4. On iPhone, follow the setup prompt to enable Call Filter under Call Blocking & Identification in Phone settings.
  5. Review Allowed Numbers and add important callers if needed.
Official Verizon guidance · Verified 2026-09-22
T-Mobile

Send Potential Spam calls to voicemail

1 min

Routes T-Mobile calls labeled Potential Spam directly to voicemail instead of letting them ring.

Keep in mind: A legitimate solicitation or unfamiliar caller could be labeled Potential Spam and go to voicemail.

Setup

  1. Open the T-Life app.
  2. Open Scam Shield.
  3. Go to the Call section.
  4. Turn on Send potential spam to voicemail.
Official T-Mobile guidance · Verified 2026-09-22
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