The short answer
- Turn on your phone's built-in protection: Silence Unknown Callers or Call Screening on iPhone, spam filtering on Android.
- Switch on your carrier's free spam blocking.
- Register with your country's do-not-call list.
- Do not answer unknown numbers, and never press a key or call back.
- Report and block the numbers that get through.
No single step stops every call, but together they cut most of them.
On iPhone
Screen or silence unknown callers
On iOS 26, go to Settings > Apps > Phone > Screen Unknown Callers. There are three choices:
- Ask Reason for Calling (Call Screening): the iPhone answers unknown numbers for you, asks the caller for their name and reason, and shows you the reply before you decide whether to pick up. Robocalls usually hang up.
- Silence: calls from numbers that are not in your contacts or recent calls go straight to voicemail.
- Never: unknown calls ring as normal.
On older iOS versions, the equivalent is Settings > Phone > Silence Unknown Callers. Downside of silencing: you may miss delivery drivers, doctors' offices or other first-time callers, so check voicemail. Apple says calls are not screened while you are roaming.
Block a number
In the Phone app, tap Recents, tap the (i) next to the number, then Block Caller.
Call-blocking apps
Apps such as those from your carrier, or established services like Hiya and Truecaller, can add to Apple's protection under Settings > Apps > Phone > Call Blocking & Identification. Read the privacy policy first: some apps upload your contacts.
On Android
Menus vary by brand, but on Google Pixel and phones using the Google Phone app:
- Open the Phone app > menu (three dots) > Settings.
- Tap Caller ID & spam and turn on See caller and spam ID and Filter spam calls.
- On Pixel phones in supported countries, open Call Screen to have Google Assistant answer unknown callers and automatically decline robocalls.
On Samsung phones: open the Phone app > menu > Settings > Caller ID and spam protection, and turn it on. You can also choose to block high-risk or all spam calls.
To block a number: in Recents, long-press the number and choose Block or Block/report spam.
Carrier tools
Most networks offer free spam-call blocking, often switched off by default.
- US: AT&T ActiveArmor, Verizon Call Filter and T-Mobile Scam Shield all have free tiers. US carriers also use STIR/SHAKEN call authentication, which helps flag spoofed numbers as "Spam Likely" or "Scam Likely".
- UK: networks block many known scam numbers automatically, and some offer extra filters. You can forward scam texts to 7726 for free.
- Pakistan: report fraudulent calls and messages to the PTA through its online complaint portal or the PTA CMS app. The PTA says it never asks for personal details by call, SMS or social media, so a caller claiming to be from the PTA is a red flag.
Check your network's website or app for the current name of its blocking service.
Do-not-call registries
| Country | Registry |
|---|---|
| US | National Do Not Call Registry: donotcall.gov or 1-888-382-1222 |
| UK | Telephone Preference Service (TPS): tpsonline.org.uk |
| Canada | National Do Not Call List (DNCL) |
| Australia | Do Not Call Register |
Registration is free and permanent in the US. It stops most legal telemarketing, but scammers ignore it.
Report the calls
Reporting helps regulators trace and shut down operations.
- US: report to the FTC at ReportFraud.ftc.gov, or on donotcall.gov for unwanted sales calls.
- UK: report scam calls to Report Fraud, or text the number to 7726.
- Elsewhere: use your telecoms regulator or national fraud reporting service.
What never to do
- Do not press a number to "be removed from the list" or "speak to an agent". It confirms your number is live.
- Do not say "yes" to a stranger's question. Short recorded answers can be misused.
- Do not call back missed calls from unknown international numbers. Some are premium-rate scams known as "wangiri" or one-ring scams.
- Do not give codes. No real bank, delivery company or government agency calls asking for a one-time passcode, PIN or password.
- Hang up and call back on a number you trust if a caller claims to be your bank or a government agency. Caller ID can be faked.
Scam texts follow the same pattern. Our guide to spotting scam texts and phishing emails covers them. If your number appeared in a breach, see how to check if your data was in a breach.
Key takeaways
- Turn on built-in filtering on your phone and your carrier's free blocking.
- Join your country's do-not-call registry, knowing scammers ignore it.
- Let unknown numbers go to voicemail, and never press keys or call back.
- Report spam calls to help regulators shut them down.