How to Block Unknown Callers on iPhone (iOS 26): Step by Step

To block unknown callers on iPhone, open Settings › Apps › Phone, scroll to Screen Unknown Callers and choose Silence. Calls from numbers that aren't in your contacts stop ringing: they go straight to voicemail and still appear in Recents, so you can check them later. If you'd rather not miss a legitimate stranger, choose Ask Reason for Calling instead.

Each option works differently. Never lets every call ring, as before. Ask Reason for Calling answers unsaved numbers for you and asks the caller who they are and why they're calling before your iPhone rings. Silence sends them all to voicemail without a sound. On the same screen, Call Filtering can move calls from unknown numbers into a separate Unknown Callers list and silence calls your carrier flags as spam.

To block one specific number, open the Phone app, tap Recents, tap the number (in Classic view, tap the Info button), scroll down and tap Block Caller. You can review everything you've blocked in Settings › Privacy & Security › Blocked Contacts, where you can also add a number by hand. Blocks apply to all your Apple devices signed in to the same Apple Account.

The catch: these settings judge a call only by whether the number is saved. Silence treats your new doctor's office exactly like a robocaller, and blocking by hand only stops numbers that have already called you, one at a time. Spam operations switch numbers constantly, so a manual block list is always one step behind.

That's where a call-blocking app adds real value. Block-Spam keeps a shared, regularly updated list of known spam numbers and blocks them through iOS before your phone rings, so you can leave Screen Unknown Callers on Never or Ask Reason for Calling and still stop spam. No account needed, and your contacts never leave your phone.