How to stop spam calls: filters, registers and cutting the supply

Breach / exposure. Updated 2026-09-13. About 4 minutes to read.

Turn on your phone's spam filter and your carrier's free blocking today, register with the Do Not Call list, and never press a key or call back.

No single setting stops every spam call. What works is layers: your phone's built-in filter, your carrier's free blocking, the national Do Not Call register for legitimate telemarketers, and removing your number from the lists that scammers buy.

Turn on the first two layers now. They take five minutes and cut the most calls. Then work on the supply, which takes longer but is the only thing that makes the number less valuable to call.

Why the calls started

Your number was in a breach or a scraped dataset that is sold to call centres.
People-search and marketing brokers list your number next to your name.
You filled in a quote form, such as for insurance, solar or loans, that sold your details as a lead.
You answered, pressed a key or called back once, which marked the number as live.
Autodialers simply try every number in a range, including yours.

Turn on your phone's built-in filter

iPhone: open Settings, tap Apps, tap Phone, find the unknown callers setting and choose Silence. Calls from numbers not in your contacts go to voicemail.
iPhone with a blocking app: in the same Phone settings, open Call Blocking and Identification to switch on your carrier's or a trusted app's filter.
Android with the Google Phone app: open the Phone app, tap More options, then Settings, then Caller ID and spam. Turn on See caller and spam ID and Filter spam calls.
Samsung phones: open the Phone app, go to Settings and turn on Caller ID and spam protection.

Silencing unknown callers also silences doctors and delivery drivers. Check voicemail daily for the first week and save genuine numbers to contacts.

Use your carrier's free blocking

AT&T: ActiveArmor has a free tier that blocks suspected fraud calls and labels spam.
Verizon: Call Filter's free version detects and filters spam calls.
T-Mobile: Scam Shield blocks scam calls at network level and has a free app.
Australia: telcos must identify, trace and block scam calls under an industry code registered by the ACMA. Ask yours about extra scam call and text blocking settings.
UK and Canada: ask your network about call blocking features, and report nuisance calls to your provider as well as the regulator.

What Scam Likely and a verified caller ID mean

Large US phone companies have had to use STIR/SHAKEN caller ID authentication since 30 June 2021. It checks whether the calling number was genuinely assigned to the caller, which is why some calls show as verified and many spoofed calls are labeled as spam.

Verified means the number was not faked. It does not mean the caller is honest. A scammer using a real number can still show as verified, so judge the call by what the caller asks for, not by the label.

Register your number, then report the calls that keep coming

US: register free at donotcall.gov or 1-888-382-1222. The FTC says sales calls can take up to 31 days to stop, and registration never expires. It does not stop political, charity, debt collection, informational or survey calls, or scammers. Report scams at ReportFraud.ftc.gov.
Australia: register at donotcall.gov.au or 1300 792 958. Telemarketers have 30 days to stop. Charities, researchers, political parties and educational institutions are exempt. Report scam calls to Scamwatch.
UK: register free with the Telephone Preference Service at tpsonline.org.uk. It takes up to 28 days. Complain about calls that continue to the ICO.
Canada: register at lnnte-dncl.gc.ca or 1-866-580-3625. Telemarketers have 31 days to stop calling.

Cut the supply at the source

Run the free phone exposure check to see where your number is likely listed.
Opt out of reverse phone lookup and people-search sites, starting with Whitepages, USPhoneBook and Spokeo.
Unlist the number from caller ID apps such as Truecaller and Sync.me.
Stop entering your real number on quote comparison and lead forms. Use a second number instead.
Re-check the listings every 90 days, because they return.

What never works

Pressing a key to be removed from the list. It confirms a live number and usually brings more calls.
Calling back a missed international number, which can be a premium rate call.
Blocking each number one by one. Spoofed calls use a different number every time.
Arguing or asking to be taken off the list. Scam call centres do not keep one.

Your bank, tax office or phone company will never ask you to read out a code sent by text. Hang up and call the number on their website.

Frequently asked questions

Does the Do Not Call list stop scam calls?

No. It stops sales calls from companies that follow the law. Scammers ignore it. Use it anyway, because the calls that remain are then easier to recognise as scams and report.

Why do spam calls come from numbers that look like my area code?

Scammers spoof local-looking numbers because people are more likely to answer. The number shown usually belongs to someone else, which is why blocking it does not help.

Is it dangerous to say yes on a spam call?

There is little evidence that a recorded yes on its own is used to approve charges. The real risk is that any answer confirms the number is live. Stay silent or hang up.

Will spam calls stop if I never answer?

They often slow down after weeks of no answers, but numbers from breach and broker lists keep being sold. Filters and removing your listings do more than waiting.

Do third-party call blocker apps sell my data?

Some ask to upload your contacts, which is how caller ID databases grow. Read the permissions before installing, and prefer your phone's built-in filter or your carrier's tool.