How to Block Spam Calls and Unknown Numbers on Android and iPhone

Your phone rings, a number you don't recognize appears, and when you answer, no one says anything or they start making an offer you never asked for. If this happens several times a day, the good news is that it's possible to... Block spam calls and unknown numbers using features that already come with Android and iPhone, in addition to free registration and help from the carrier.

In this step-by-step guide, you'll see each path, from the simplest to the most complete. You don't need to do everything: choose the options that best suit your needs.

Before we begin: block, mute, or identify?

It's important to understand the difference between the three options, because each one solves a part of the problem:

• Block: It prevents a specific number from calling you again. It works well for those who keep calling the same number.
• Silencing strangers: Calls from numbers not in your contacts will not ring. They will go to your call history and voicemail.
• Identify and filter spam: The phone consults a database of reported numbers and alerts (or blocks) calls that appear suspicious.

How to block spam calls on Android

The menu names may vary slightly depending on the brand and system version, but the path is usually similar.

Activate the spam filter in the Phone app.

1. Open the app Telephone.
2. Tap the three dots in the corner of the screen and enter settings.
3. Look for the option Spam and caller ID (or Caller ID and spam protection, (in some models).
4. Enable caller ID and the option to filter spam calls.

As a result, calls marked as spam either stop ringing or appear with a warning on the screen, depending on the device.

Block a specific number

1. In the Phone app, open the tab Recent.
2. Tap and hold the number you want to block.
3. Choice Block or Block/report spam.

By reporting, you also help improve the database of suspicious numbers used by others.

Block hidden and unknown numbers

On various Android devices, within settings From the Phone app, there is the option Blocked numbers. There you can activate call blocking for unknown or private numbers, Those that appear as "Hidden Number." Use with caution: delivery drivers and clinics sometimes call from numbers that are not in your contacts.

How to block spam calls on iPhone

Silence unknown numbers

1. Open Adjustments.
2. Enter apps and then in Telephone (In older versions of iOS, Phone appears directly in the Settings list).
3. Activate Silence Strangers.

In the latest versions of iOS, this area also offers filters for unknown calls, such as asking the caller to state their identity and the reason for the call before the phone rings. The exact name may vary depending on the version.

Block a contact or number

1. In the Phone app, open Recent.
2. Tap the icon. (i) next to the number.
3. Scroll to the bottom and tap Block this contact.

On iPhones, the block applies to calls, messages, and FaceTime from that number.

Using ID apps on iPhone

After installing a caller ID app, you need to authorize it in Settings > Apps > Phone > Call Blocking and Caller ID. Without this step, the app cannot notify you of or block calls.

Official registration against telemarketing.

Many countries have an official, free list for people who don't want to receive offers by phone. After registering, participating companies are prohibited from calling that number with commercial offers.

• Brazil: Registration is done on the website. Do Not Disturb Me, This applies to offers of telecommunications services and payroll loans. In Brazil, outbound telemarketing calls must also use the prefix. 0303, This makes it easier to recognize and block these calls.
• Other countries: Look for your country's national anti-telemarketing registry, such as the National Do Not Call Registry in the United States, the Lista Robinson in Spain, or Bloctel in France.

Important: these registrations do not block scammers, who do not follow the rules. They reduce offers from legitimate companies. Therefore, combine registration with your mobile phone's filters.

Operator resources

Some carriers offer caller ID and spam blocking services, either free or included in their plan. To find out if your carrier offers this option, check their official app or website, or call customer service using the number on your bill. Do not use numbers or links received via text message for this purpose.

Caller ID apps: how to choose

Caller ID apps use databases of numbers reported by millions of users and often recognize spam faster than the native filter. Before installing one, note:

• Origin: Download only from your phone's official app store (Google Play or App Store).
• Reviews: Check the rating and read the most recent comments, not just the first ones.
• Permissions: Check what the app is asking for. Access to the call log makes sense; asking for access to everything without explanation is a red flag.
• Privacy: Some apps send your contact list to their own database. Read the privacy policy and disable contact sharing if that option is available.
• Cost: Many apps offer a free version with the essentials. Consider whether the paid version includes something you'll actually use.

What not to do when answering an unknown number

• Do not confirm your full name, documents, or address.
• Do not provide codes received via SMS during the call.
• Do not press any keys when a recording asks you to “press 1 to…”.
• Do not make payments or transfers for requests made over the phone.
• If they say it's from your bank, hang up and call the number printed on your card yourself.

See too:

• Phone and text message scams: how to protect yourself
• How to block spam and scam calls on your cell phone.
• Apps to free up phone memory
• How to make your cell phone faster

Conclusion: fewer calls, more peace of mind

For most people, activating their phone's spam filter and blocking persistent numbers already solves a large part of the problem. If the calls continue, add the official anti-telemarketing registry and, if you wish, a well-reviewed caller ID app. No solution blocks all calls, but together they make your day much more peaceful.

Want to understand the most common phone and text message scams and how to protect your family? Read our guide too! Phone and text message scams: the most common ones and how to protect yourself..