How to Block Spam Calls on iPhone in iOS 27

Blocking a spam number on iPhone still has a place, but it is no longer the best first defense against modern nuisance calls. Robocallers and scammers can rotate numbers, while legitimate callers—your doctor, a delivery driver, a school, a contractor—may also call from numbers you have never saved.

In iOS 27, the Phone app gives you several separate controls: Call Screening can ask an unknown caller for a name and reason before your iPhone rings; Spam filtering can silence calls your carrier identifies as spam or fraud; Unknown Callers can move unsaved callers into a separate list; and traditional blocking can stop a specific number or contact. The useful setup is to give each tool the job it is actually good at.

Blocking one number is the wrong tool for rotating spam

A manual block is precise: it is useful when the same unwanted number keeps calling. It is much less effective when nuisance calls arrive from a different number each time. Blocking yesterday's number does not create a rule against tomorrow's spoofed or newly generated number.

For repeated calls from one number, open the Phone app, open that caller's contact card from your call history, and choose Block Contact. Apple notes that a blocked caller can still leave voicemail, but you do not receive a notification for it. The caller is not told that you blocked them.

That distinction matters. If your problem is one persistent person or business, block the number. If your problem is a stream of unrelated unknown numbers, use screening and filtering instead.

Call Screening is the middle ground between ringing and silence

Apple's current iPhone guide describes three ways to handle calls from unsaved numbers under Settings > Apps > Phone: Never, Ask Reason for Calling, or Silence.

Ask Reason for Calling is the most useful choice for many people who receive both spam and legitimate first-time calls. The iPhone answers an unknown call without interrupting you and asks the caller to provide their name and reason for calling. Your phone then rings with that response so you can decide whether to answer.

This changes the trade-off. You do not have to let every unknown number ring immediately, but you also do not have to send every unsaved caller straight to voicemail. Someone with a real reason to reach you can identify themselves before you pick up.

Silence is more aggressive. Unsaved callers are silenced and sent to voicemail. It can be appropriate when interruptions matter more than missing an unexpected call, but it is a poor default for people waiting for medical offices, schools, job recruiters, service technicians, couriers or other legitimate callers whose numbers are not already in Contacts.

Carrier spam filtering solves a different problem

iOS 27 also has a Spam filter in the Phone app's call-filtering controls. When enabled, calls that your carrier identifies as potential spam or fraud are silenced, sent to voicemail and moved to the Spam list.

The important limitation is in that wording: the carrier has to identify the call. The iPhone is not independently proving that every unknown number is fraudulent. A call that is not labeled by your carrier can still reach the unknown-caller workflow, and carrier detection can vary by provider and region.

That is why Spam filtering and Call Screening work well together. The carrier filter can remove calls already classified as suspicious, while screening gives unlabeled unknown callers a chance to state why they are calling.

The Unknown Callers filter is organization, not the same thing as screening

Another iOS 27 option can move missed calls and voicemails from unknown numbers out of the main call list and into an Unknown Callers list. In the Phone app, use the Filter button to view Unknown Callers or Spam.

This is easy to confuse with silencing or screening because all three deal with unfamiliar numbers. Their jobs are different:

• Call Screening: controls what happens before an unknown call interrupts you.
• Silence: sends unsaved callers to voicemail without ringing.
• Unknown Callers filter: separates those calls in call history so your main list is cleaner.
• Spam filter: handles calls your carrier has identified as potential spam or fraud.

You can also mark an unknown caller as Known from the Unknown Callers list. That is useful after a legitimate first contact because future calls from that number do not need to keep being treated as unknown.

Caller identification can come from more than your Contacts

Incoming caller information can come from several sources. Apple lists Contacts, Name and Photo Sharing, supported carrier directories, Business Call Identification and supported call-identification apps.

If you use third-party caller ID apps, go to Settings > Apps > Phone > Call Blocking & Identification. iOS 27 lets you prioritize installed identification apps, so one service can be consulted before another. This is more useful than installing several caller-ID apps and assuming they all operate with equal priority.

Third-party identification is optional, not a requirement for Apple's built-in screening. If you prefer to minimize the number of services involved, try the built-in Phone controls and your carrier's spam identification first, then add an identification app only if it solves a gap you actually have.

A low-risk setup for people who cannot miss unknown calls

If your work or family life regularly produces legitimate calls from new numbers, do not jump straight to silencing every unsaved caller. A more forgiving configuration is:

1. Save genuinely important recurring numbers—family, school, doctors, workplace and key services—in Contacts.
2. Set unknown-call handling to Ask Reason for Calling.
3. Enable the carrier-backed Spam filter if it is available for your service.
4. Enable the Unknown Callers list if you want a cleaner main call history.
5. Block individual numbers only when a specific caller repeatedly causes a problem.

This setup adds friction for unknown callers without assuming that “not in Contacts” means “spam.”

Silence is better when interruption itself is the problem

There are situations where screening is still too permissive. If you are being flooded with nuisance calls and do not expect legitimate unsaved callers, choosing Silence can be more appropriate. Unknown calls go to voicemail rather than ringing.

The cost is false negatives: a legitimate caller can be quieted too. Before using this as a permanent setting, think about the calls you receive outside your saved contacts. A person who rarely receives new business, medical, school or delivery calls has a different risk profile from a freelancer, caregiver or small-business owner.

If you later discover a legitimate caller in the Unknown Callers list, mark that number as known or save it to Contacts.

Two exceptions can explain why screening behaves differently

Apple documents two details that are easy to miss when troubleshooting Call Screening. Phone calls are not screened while you are roaming, regardless of the setting. And after you call emergency services, Call Screening is disabled for 24 hours.

Those are important diagnostic facts. If screening suddenly appears to have stopped during international travel, changing the same setting repeatedly will not solve the roaming limitation. Likewise, different behavior after an emergency call can be intentional rather than a Phone-app failure.

When spam still rings, diagnose the layer that failed

If an unwanted call still gets through, its path tells you what to check.

• A saved contact is unwanted: screening for unknown callers is not relevant; block that contact or number.
• An unsaved number rings without screening: check the unknown-caller setting under Settings > Apps > Phone, and remember the roaming and emergency-call exceptions.
• A suspected spam call is not moved to Spam: it may not have been identified as spam by your carrier. Carrier filtering is classification-based, not a guarantee against every nuisance call.
• A caller-ID app is not identifying calls as expected: check Call Blocking & Identification and the priority order of installed identification apps.
• Your main call history is cluttered: enable the Unknown Callers filter; that is an organization problem rather than a reason to silence every unknown call.

This diagnostic order is safer than changing several Phone settings at once, because you can see which layer actually changes the behavior.

Spoofed caller ID is why the displayed number is not proof

Spam control has a limit that no iPhone setting can remove: caller ID can be spoofed. The U.S. Federal Communications Commission maintains consumer guidance and a complaint process for unwanted calls, texts and number spoofing. If a caller claims to represent a bank, government agency or company and asks for money, credentials or sensitive information, do not treat the displayed number as proof of identity.

End the call and contact the organization through a number or app you independently know to be legitimate. Blocking the displayed number may stop that exact number from contacting you again, but it does not verify who made the original call.

The best spam-call setting depends on the calls you need to keep

For most iPhone owners, the useful goal is not “block every unknown number.” It is to reduce interruption without making legitimate first-time callers disappear.

Use Call Screening when you want unknown callers to explain themselves before your phone rings. Use carrier Spam filtering for calls already classified as suspicious. Use the Unknown Callers list to keep call history organized. Use Silence when you accept the risk of missing unsaved callers. And block individual numbers when the nuisance is tied to a specific caller.

Apple's current documentation for these controls is available in its Screen and block calls on iPhone and Phone settings guides. For persistent illegal calls or caller-ID spoofing in the U.S., the FCC unwanted-calls complaint guide explains the reporting categories.