Apple doesn't allow blocking unknown numbers
The iPhone operating system doesn't currently allow any app to block calls from unidentified or unknown numbers. This is an Apple limitation, not a Hiya Spam Blocker limitation.
What you can do instead
Enable Silence Unknown Callers — go to iPhone Settings → Phone → Silence Unknown Callers. Calls from unknown numbers will be silenced and sent to voicemail.
Use Call Screener (Premium) — unknown callers are prompted to state their name and reason for calling before your phone rings.
Block specific prefixes — use "Numbers that begin with" in the Block List to block common spam area codes.
June 4, 2026 - v9.x, 10.x