How to Block Spam Calls on iPhone and Android (The Carrier Code Most Guides Skip)

Dialed #662# on a whim after reading it buried in a T-Mobile support thread, half expecting nothing to happen. A text came back within seconds confirming spam blocking was now active on the line — no app, no settings menu, just a phone code most people have never heard of. Genuinely surprised something that simple actually worked, especially after years of half-measures that barely dented the daily robocall count.

Spam calls in 2026 aren’t going away — spoofing technology has gotten good enough that blocking one number just means the same scammer calls back five minutes later from a different one. But there’s a real layered approach that actually cuts the volume down, and it starts with settings most phones already have built in.

Sources: Apple Support, Google Support, T-Mobile Support, FTC.gov. Verified July 2026.

iPhone: Silence Unknown Callers vs Call Screening

Settings → Phone → Silence Unknown Callers sends anything from a number not in contacts, messages, or email straight to voicemail. It’s the bluntest tool available, and here’s the part that trips people up: it silences everyone, not just scammers. A delivery driver calling about a gate code, a recruiter following up on an application, a new dentist’s office — all of it goes straight to voicemail with zero ring.

Learned that one the hard way after missing a callback about a repair appointment for two days, only noticing when the voicemail badge finally got checked. Turned out the setting had been left on since a spam wave the month before, and it quietly kept doing its job long after the spam had died down.

iOS 26’s “Ask Reason for Calling” is the gentler middle ground — unknown callers get prompted to state their name before the phone even rings, and a live transcript shows up so there’s a chance to pick up if it’s legitimate. Scammers almost universally hang up the second they hear the automated prompt.

Expecting calls from unknown numbers soon — job hunting, medical appointments, a delivery? Use Ask Reason for Calling instead of Silence Unknown Callers, or check voicemail daily without fail.

Android: Caller ID & Spam Filtering

On Pixel and most Android phones running the Google Phone app: Settings → Caller ID & Spam → toggle on See caller and spam ID and Filter spam calls. Google checks incoming numbers against a constantly updated spam database and flags or auto-rejects known offenders before the phone even rings.

Call Screen takes it further — Google Assistant answers on your behalf, asks who’s calling and why, and shows a real-time transcript. Here’s where it actually gets interesting: this works well enough that most scam callers hang up mid-sentence once they realize they’re talking to an AI screener, not a person who might fall for the script.

The Carrier Code Nobody Mentions

T-Mobile customers can dial #662# directly to activate Scam Block at the network level — free, built-in, no app download required. This blocks calls the carrier’s own systems have already flagged as fraud before they ever reach the device, working as a layer underneath whatever the phone’s own settings are doing.

AT&T and Verizon customers have similar carrier-side tools (AT&T Call Protect, Verizon Call Filter), usually bundled in free or accessible through the carrier’s app. Checking whether the specific carrier has an equivalent shortcut code is worth five minutes — it’s a layer most spam-call guides skip entirely, probably because it varies by carrier and doesn’t fit neatly into a generic phone-settings tutorial.

On T-Mobile and haven’t dialed #662# yet? That’s the single fastest fix in this entire list — no menus, no app, just one phone call.

For a related angle on protecting the account behind that phone number — not just the calls coming into it — the number porting and account security guide covers the settings that stop someone from hijacking the number entirely, not just spamming it.

Third-Party Apps: When Built-In Isn’t Enough

Apps like Hiya, RoboKiller, and Truecaller maintain their own spam number databases, often catching numbers days before carrier systems flag them. Worth it for anyone still getting hit hard after enabling everything above — though most people find the built-in layered approach (carrier code + phone settings) handles the bulk of it without needing a separate subscription.

The FTC Registry: Honest Expectations

The Do Not Call Registry (donotcall.gov, or 1-888-382-1222) removes a number from lists legitimate telemarketers are legally required to check. What it doesn’t do is stop actual scammers — by definition, the people breaking the law aren’t checking a legal compliance list before dialing. Signing up costs nothing and helps with the legitimate-telemarketer side of things, but it’s not the fix for robocall scammers specifically.

Getting mostly scam calls, not legitimate telemarketers? The FTC registry won’t move the needle much — the carrier code and phone settings above are doing the real work.

Why Blocking One Number Never Fully Works

Here’s the part that’s genuinely counterintuitive the first time you notice it: spoofing lets scammers fake caller ID to show a local area code, or a number that changes every single call. Blocking one number after a spam call feels productive in the moment, but the same operation is often calling back within the hour from a number that looks completely unrelated.

That’s exactly why the layered approach — carrier code plus phone settings plus, if needed, a third-party app — matters more than any single fix. No one layer catches everything on its own.

Frequently Asked Questions

Does blocking a spam number actually stop them from calling again?
Not reliably — spoofing lets scammers use a different fake number for each call, so blocking one number rarely stops the same operation for long.

What does #662# do on T-Mobile?
It activates Scam Block at the network level, blocking calls T-Mobile’s systems have already flagged as fraud before they reach the phone — free, no app required.

Does the FTC Do Not Call Registry stop scam calls?
It removes a number from lists legitimate telemarketers must legally check, but it has no effect on illegal scam or robocall operations, which ignore it entirely.

Should I turn on Silence Unknown Callers?
It’s effective against spam but also silences legitimate calls from numbers not saved in contacts — useful during heavy spam waves, less ideal when expecting calls from new numbers like recruiters or delivery drivers.

Curious how bad the spam call situation has gotten where you are — worth comparing notes if this actually cuts it down for you too.