How to Block Unknown Numbers on iPhone & Android

iPhone and Android Block Unknown Numbers

Unwanted phone calls have become increasingly common across the United Kingdom. Many people receive calls from unknown, withheld, or suspicious numbers every day. Some of these calls may simply be telemarketing attempts, while others may involve scam activity designed to obtain personal information.

Fortunately, both iPhone and Android devices include built-in tools that help you block unknown callers, silence private numbers, and manage spam more effectively. This guide explains the practical steps you can take to reduce nuisance calls and protect your privacy.

Why Do Unknown Numbers Call You?

Unknown numbers may appear for several reasons. Some callers hide their number intentionally, while others may be using automated dialling systems that display temporary numbers.

Telemarketing companies promoting products or services
Automated robocalls or recorded marketing messages
Scam calls pretending to be banks, delivery companies or government services
Legitimate businesses calling from centralised switchboards
Individuals who have withheld their caller ID

How to Block Unknown Numbers on iPhone

Step 1 – Open Settings

Go to the Settings app on your iPhone and scroll down until you find the Phone section.

Step 2 – Find "Silence Unknown Callers"

Inside the Phone settings menu, locate the option called Silence Unknown Callers.

Step 3 – Enable the Feature

Turn this option on. Calls from numbers that are not saved in your contacts will automatically be silenced and sent to voicemail.

Step 4 – Check Recent Calls

Even though the call will be silenced, it will still appear in your recent calls list. This allows you to review missed calls later.

How to Block Unknown Numbers on Android

Android phones may vary slightly depending on the manufacturer, but the basic process is usually similar across most devices.

Step 1 – Open the Phone App

Launch your device’s default Phone application.

Step 2 – Access Call Settings

Tap the three-dot menu in the top corner and open Settings.

Step 3 – Find Blocked Numbers

Navigate to Blocked Numbers or Call Blocking depending on your Android version.

Step 4 – Enable Unknown Number Blocking

Activate the option to block unknown or private numbers.

Extra Ways to Stop Spam Calls

Important: Blocking unknown numbers can reduce nuisance calls, but scammers often use normal-looking numbers. Because of this, additional protection methods may be useful.

Use trusted call-blocking apps with spam detection
Report suspicious numbers online
Avoid answering calls from numbers you do not recognise
Never share personal or financial information over the phone
Keep your phone software updated for improved security

How Reporting Numbers Helps Other Users

Many phone lookup websites allow users to share their experiences with unknown numbers. When people report scam calls, spam messages, or suspicious activity, it becomes easier for others to identify potential risks.

Checking a number before calling back can help you determine whether the caller is legitimate or whether other users have already flagged the number as suspicious.

Frequently Asked Questions

Will blocking unknown numbers stop all spam calls?

No. Some spam callers use standard phone numbers that appear legitimate. Blocking unknown numbers mainly stops calls where the caller ID is hidden or withheld.

Can legitimate calls be blocked by mistake?

Yes. If someone calls you from a number that is not saved in your contacts, the call may be silenced. It will still appear in your call history so you can return the call if necessary.

Should I call back missed numbers?

If you do not recognise the number, it is safer to search the number online first. Many scam calls rely on people calling back unknown numbers.

Is it safe to answer unknown numbers?

Answering an unknown number is not always dangerous, but it is important to avoid sharing personal details unless you are certain about the caller’s identity.