Spam calls are annoying at best and dangerous when they impersonate banks, delivery companies, government agencies, or tech support. No single switch blocks every call, but a few layers together can sharply reduce them.
Does this affect you?
Use this for iPhone or Android on major U.S. carriers such as AT&T, Verizon, T-Mobile, and many smaller providers with similar call-filtering tools.
Turn on your phone’s built-in spam protection
Start here because the setting is already on the phone.
On iPhone:
- Open Settings > Phone.
- Turn on Silence Unknown Callers.
- Calls from numbers outside Contacts, Recent Calls, and Siri Suggestions go to voicemail instead of ringing.
- Check voicemail regularly so you do not miss legitimate calls from doctors, schools, delivery drivers, or businesses you have not saved.
On Android:
- Open the Phone app.
- Tap the three-dot menu or profile icon, depending on your phone.
- Open Settings > Caller ID & spam, or the closest matching option.
- Turn on See caller and spam ID or Filter spam calls.
- If available, enable Verified Calls so legitimate businesses can show extra caller information.
Turn on your carrier’s free call blocking
Major U.S. carriers provide spam detection tools, and many useful features are free.
- Find your carrier’s service, such as AT&T ActiveArmor or Call Protect, T-Mobile Scam Shield, or Verizon Call Filter. Smaller carriers often offer similar tools.
- Install the carrier app from the App Store or Google Play, or check whether the feature is built into your phone settings.
- Open the app and make sure spam labeling or blocking is enabled.
- Use automatic blocking for calls the carrier strongly identifies as fraud, and labeling for less-certain calls so real calls are less likely to disappear.
- Review the app’s call history occasionally and mark legitimate numbers as not spam if needed.
Register with the Do Not Call Registry
This will not stop criminals who ignore the law, but it can reduce legitimate telemarketing calls and gives you a reporting path.
- Go to donotcall.gov, or call 1-888-382-1222 from the phone number you want to register.
- Enter your phone number and email address if using the website.
- Confirm the registration through the email you receive.
- Allow up to 31 days for the registration to take full effect.
- Report calls that continue after that through the same site.
More control
Blocking one number is rarely enough
Scammers often spoof caller ID, including local numbers or even numbers that look like your own. Pattern-based filtering from the phone and carrier works better than chasing individual numbers.
Do not press numbers to be removed
A robocall that says press 1 to stop calls may be testing whether your number is active. Hang up instead.
Check privacy before third-party apps
Extra call-blocking apps can help, but some rely on access to call data or contacts. Built-in phone tools plus carrier filtering cover a lot before you share more information.
Sources
- Federal Trade Commission – National Do Not Call Registry (2025)
- Federal Communications Commission – Stop Unwanted Robocalls and Texts (2025)
- Apple Support – Silence unknown callers on iPhone (2025)