Blocking Unwanted Calls and Text Messages in Signal App (Android & iOS)

For various reasons, you may want to block a user from calling or sending you text messages. Some of the most common reasons for blocking a person are usually associated with privacy and security concerns, however, there could be many more reasons, which I am not going to list here because they are too obvious, and most people are familiar with them.

This article applies to the popular Signal Private Messenger app that’s available for Android and iPhone. If you’re not familiar with Signal, check out my article How to Make Signal Private Messenger Your Default Messaging App.

The Story Behind This Article

What prompted me to write this article was a text message I received from an area code in another U.S. state. The text appeared to be a phishing attempt. The phone number was most likely spoofed because I discovered that the number belongs to a 71-year-old man. You might be thinking, can’t a person that age be a cybercriminal? Yes, he could. However, it’s unlikely that a person who has lived in the same state for 23 years, lived in the same house for 15 years, has six different emails, has used six wireless phone numbers over the years, and owns one landline published on the Internet would be a cybercriminal. Obviously, the spammer had spoofed this man’s phone number.

Here’s a slightly modified version of the text. I’ve changed the actual domain name to domain.com.

“Package Tracking. Hi, your parcel with tracking code KXLP6VM is waiting for you to check the shipping address: domain.com/viktdpq.”

Obviously, this message is not from Amazon or another legit company. The tracking code doesn’t belong to FedEx, UPS, or USPS and they don’t have my phone number anyway. Also, Amazon and other vendors don’t have my phone number. The person who sent me the text doesn’t know my name. I looked up the actual domain name to check its validity. Some major websites reported it as legit, so I looked it up in the Whois database and discovered that the domain was registered on the same day when I received the text. Obviously, there was no history to track in just a few hours after it was registered. That’s why it wasn’t going to show up on any blacklists. There wasn’t a public website associated with the domain anyway. I wasn’t surprised to find out on https://sitecheck.sucuri.net/ that the domain contained a malware and had a suspicious conditional redirect to Google.

I blocked the number and thought it would a good idea to write an article for those who are not familiar with blocking unwanted texts and phone calls in the Signal app. Even if you don’t use the Singal app, you’ll find instructions for blocking calls and texts from unwanted numbers within Android and iPhone in this article.

Recommended Actions for Blocking Unwanted Texts

Here are my recommendations for blocking users who are sending you unwanted text messages. I suggest you follow my steps as described below exactly in the order they are listed.

1. Write down the phone number in the text message on a piece of paper.
2. Do not click any links in the text message.
3. Block the number within Signal, so you won’t receive calls or texts from this number in the future. See the instructions on blocking the number in the sections below.
4. Add the number to the blocked list in the OS (Android, iOS, etc.).
5. Delete the message in Signal. This won’t delete the phone number you added to the Signal app or the OS.

You always want to think ahead and not look at the security/privacy issues just in the present. Therefore, it’s important to add the blocked number both to the Signal app and the OS. This is a precautionary measure in case you had to remove or reinstall Signal app on your smartphone. You may discover that at times you have to temporarily switch your messaging app to the default app in Android or iPhone either for testing or for some other reason. It’s better to be safe than sorry.

Options for Blocking Unwanted Numbers

Here’s how you can block and unblock numbers in the Signal app. There are two options available to you. I recommend as a best practice you use both of the following options. In the context of blocking, the term user and number can be used interchangeably because it’s the phone number you are blocking that belongs to a user.

1. Take action within your smartphone’s OS (e.g., Android or iOS) to block the numbers.
2. Block numbers within the Signal app.

Blocking Numbers Within the Android Operating System

If you own an Android phone running OS version 12 and you want to block a user’s number who’s already in your Contacts, simply search for the person. When you block a number, you won’t receive calls or texts from that number.

1. Tap the person’s name in the Contacts list to access the details.
2. In the upper right corner tap More options (three vertical dots) menu.
3. Tap Block numbers. When you block a number, you won’t receive calls or text from that number. It will simply be discarded.
4. If you want to report this number as a spam, leave the box Report as spam checked and then tap Block. Otherwise, clear the box and then tap Block.
5. The user is now blocked, so you won’t receive calls or texts from the user. You will see a red circle with a line across the circle next to the phone number, indicating the user is blocked.
6. To unblock the user, go back to the More options menu and tap Unblock numbers.
7. You will see a prompt that you may receive calls or texts from this phone number. Tap Unblock. The user is no longer blocked.

Blocking Numbers Within the iPhone Operating System

If you own an iPhone running iOS 15 follow the instructions provided by Apple. You can block the following.

1. Voice calls.
2. FaceTime calls.
3. Text messages.

Blocking Numbers Within the Signal App

To block users from Signal app, follow these steps. These steps worked at the time of writing. However, depending on when you read this article, the app may have been updated and the options may not be the same.

1. Open the Signal app on your smartphone.
2. Open the Contact that you want to block. This will contain the text message(s) from that person.
3. Tap More options (three vertical dots) in the upper right corner.
4. Tap Conversation settings.
5. Scroll down to the bottom of the screen and tap Block. It will be the only option that’s in red.
6. You’ll see a prompt “Blocked people won’t be able to call you or send you messages”, with an option to Cancel or Block. Tap Block.
7. The option changes color and now displays Unblock in black. If you change your mind later, you can unblock the person.
8. When you tap the back arrow, you’ll see the option to Unblock in blue and Delete in red. You can tap Delete to get rid of their message history. This is important if the person was a spammer. Their images, URLs, etc. may be harmful so it’s best that you get rid of all the messages.

Viewing the Blocked List in Signal

All blocked numbers are added to a blocked list in Signal. To see the list, follow these steps.

1. Open the Signal app.
2. Tap on your profile icon. Your profile is the round icon in the top left corner with your initials. Another way to get to the same screen is to tap More options (three vertical dots) in the upper right corner and then tap Settings. Tapping on profile saves you this extra step because it takes you straight into the settings.
3. Tap Privacy.
4. Tap Blocked to see the numbers that have been blocked. You can’t add numbers here. This area only displays the list of blocked users who can’t call or text you. You can, however, unblock a user by tapping their phone number and then tapping Unblock.

Keep in mind that if the person who texted or called you was spoofing the number, all you can do is block the number that was used. Unfortunately, the spammer scan spoof a different phone number to text or call you and there’s not much you can do about it. You can, however, use an app that displays caller ID of the habitual spammers. One such app is Hiya. It gives you more information about the caller and can block robocalls. Hiya is available for Android and iOS devices.

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