Block spam calls on iPhone — free
Your iPhone already ships with everything on this page. Here's every switch, what it actually does, and the trade-off behind each one.
1. Silence Unknown Callers — the big hammer
Settings → Apps → Phone → Silence Unknown Callers → on. (On older iOS: Settings → Phone.) Any number not in your contacts, recent outgoing calls, or Siri suggestions goes straight to voicemail without ringing. It is the single most effective free setting on this page.
The trade-off Apple undersells: it silences everyone you haven't saved — the new dentist confirming your appointment, the delivery driver at your gate, the school nurse. If you're waiting on a callback from anyone new, this setting will eat it. That's the gap conversational screening exists to close.
2. Live Voicemail — read the call while it happens
On iOS 17 and later, when a silenced or declined call hits voicemail, the transcript appears live on your screen while the caller is still talking. Real person leaving a real message? Tap to pick up mid-sentence. Robot reading a script about your car's extended warranty? Watch it hang itself. Turn it on at Settings → Apps → Phone → Live Voicemail.
3. Block individual numbers
Phone app → Recents → tap the ⓘ next to the number → Block this Caller. Worth doing for repeat offenders, but know the limits: spammers rotate spoofed numbers constantly, so manual blocking is whack-a-mole. Blocked callers go straight to voicemail and can still leave messages.
4. Filter spam texts too
Settings → Apps → Messages → Filter Unknown Senders puts texts from strangers in a separate tab with notifications off. Under any junk text, tap Report Junk — it deletes the message and reports the sender to Apple and your carrier. Full text playbook: stop spam texts.
5. Add the carrier layer
Your carrier runs a free network-level filter that catches spam before your iPhone ever sees it — but most lines don't have it fully enabled. Guides: AT&T ActiveArmor, Verizon Call Filter, T-Mobile Scam Shield.
What the free stack still misses
Everything above filters by number reputation. A fresh spoofed number has no reputation, so it rings through — and the moment you answer one, your number gets flagged "live" and sold again (here's why you're suddenly getting so many). Spam Slayer closes the loop by answering unknown calls conversationally: real humans get passed through to you in seconds, robots and boiler rooms get the crew.