No single setting stops every spam call, but combining your phone’s built-in filtering, your carrier’s free tools and your national do-not-call registry cuts most of them. Never press a key or call back to “opt out”.
Why spam calls are so hard to stop
Robocalls are cheap to make in bulk, caller ID can be faked, and many come from overseas, outside the reach of local rules. Blocking one number rarely helps, because the next call comes from a different one. The goal is to filter calls by behavior and reputation rather than chase individual numbers.
The good news is that phones and networks now do a lot of this filtering for you, once you switch it on.
On iPhone
Apple puts its call filtering options in the Phone section of the Settings app. The exact location and names can change between iOS versions, so if you can’t find an option, search for it using the search bar at the top of Settings.
- Silence Unknown Callers. Calls from numbers that aren’t in your contacts, recent outgoing calls or Siri Suggestions are silenced and sent to voicemail. They still appear in your recent calls list. This is very effective, but you may miss legitimate first-time callers such as a doctor’s office or a delivery driver, so check voicemail regularly.
- Call screening. Recent iOS versions can ask unknown callers for their name and reason for calling before your phone rings, so you can decide whether to pick up. Availability depends on your iOS version and region.
- Call Blocking & Identification. This is where you enable third-party spam-blocking apps, including your carrier’s app if it offers one.
- Block a single number. In Recents, tap the info button next to a number and choose to block the caller.
On Android
Android phones vary by manufacturer. Many use the Google Phone app; others, such as Samsung, use their own dialer with similar features.
- Google Phone app. Open the app, tap the menu, go to Settings and look for the caller ID and spam section (labeled “Caller ID & spam” or similar, depending on the version). Turn on caller ID and spam identification, and turn on filtering of spam calls if you want suspected spam to skip ringing entirely.
- Call Screen. On some phones and in some countries, the Google Phone app can answer unknown callers for you and show a live transcript.
- Samsung and other brands. Look in the Phone app’s settings for a caller ID and spam protection option.
- Block a single number. Long-press the number in your call history and choose Block, or Block/report spam.
Use your carrier’s tools
Many mobile carriers offer free spam call labeling and blocking, sometimes with a paid tier for extra features. These work at the network level, so they can flag or stop a call before it reaches your phone. Search your carrier’s website or app for “spam call blocking”, or ask customer support what is included in your plan.
Landline providers often offer similar options, including anonymous call rejection, which blocks calls that hide their number.
What STIR/SHAKEN does, in plain terms
STIR/SHAKEN is a set of technical standards used by phone networks in the US and Canada. When a call starts, the originating carrier digitally “signs” it to say how confident it is that the caller is allowed to use the number shown. The receiving carrier checks that signature.
It doesn’t block calls by itself. It helps carriers spot spoofed numbers, label calls and trace robocalls back to their source. Some phones show a “verified” mark for calls that passed the check. Calls that pass through older networks or come from abroad may not carry a signature, so spoofed calls can still get through.
Sign up for your national do-not-call registry
Do-not-call registries tell legitimate telemarketers not to call you. Examples include the National Do Not Call Registry in the US (donotcall.gov), the Telephone Preference Service in the UK, the National Do Not Call List in Canada, the Do Not Call Register in Australia, and the “Do Not Disturb” preference service run under India’s telecom regulator.
Registration is free on the official services. It reduces calls from companies that follow the law. Scammers ignore it, so registration alone won’t stop fraud calls. Calls that ignore a registry you have joined are themselves a red flag.
Never press a key, say “yes” or call back to be “removed from the list”. This only tells the caller your number is active.
What to do: a simple setup that works
- Turn on your phone’s spam filtering (Silence Unknown Callers or call screening on iPhone; caller ID and spam filtering on Android).
- Activate your carrier’s free spam protection, through its app or account settings.
- Register with your national do-not-call list using the official website only.
- Don’t engage with robocalls. Hang up without pressing anything.
- Check unknown numbers before calling back. Search them on MobileTracking to see the spam score and community reports.
- Report spam numbers to your phone, your carrier and on our report form. In the US, you can also report unwanted calls at ReportFraud.ftc.gov or donotcall.gov.
What not to expect
Filtering will occasionally catch a call you wanted, and some spam will still slip through. Review your blocked or spam folder now and then, and keep voicemail set up so genuine callers can leave a message. If a caller claims to be your bank, a government office or a tech company, the safest move is to hang up and contact them through a number you already trust. Our guides on bank impersonation calls and one-ring scams explain why.
This guide is general information, not legal or financial advice. Read our editorial policy.