How To Block Unknown Text Messages on Your Phone (2025)

Text scams are on the rise, and most of them come from unknown numbers. These messages might look legitimate, but they’re often designed to trick you into clicking a malicious link or handing over private information.

Is everyone getting spam texts? Pretty much, in 2023 alone, people lost about $470 million to scam texts (Robokiller, 2023)¹ — that’s five times more than in 2020. If you continue to receive suspicious texts, it’s a sign that your number may be on a spam list.

The process of blocking spam texts depends on your phone and messaging app, but most devices offer built-in tools to filter or block unknown senders. In this guide, I’ll show you how to stop unknown texts across different devices and apps, plus a few extra tips to keep your number private and reduce future spam.

How To Block Unknown Text Messages on Your Phone

Is there a way to block unknown text messages? The steps to blocking unknown text messages depend on your phone and the messaging app you're using. Still, it's worth doing. In 2024, the FTC received over 350,000 complaints about scam texts (Federal Trade Commission, 2025)³. Even worse, it’s estimated that Americans have lost over $300 million in some years due to these scams (USA Facts, 2023)⁴.

How To Block Unknown Text Messages on Android

There are two ways you can block text messages on Android: via the phone messaging app and or Google messaging app.

Through the Phone Messaging App

1. Open the Phone app, tap the three dots in the corner, select Settings, and go to Blocked Numbers.
   After clicking a new window will pop up
2. Block unknown numbers. To block someone, simply type their phone number into the Add phone number box and then tap the plus (+) icon. If you want to block all calls from numbers you don’t know, turn on the option labeled "Block calls from unknown numbers."
   You can also fetch the number you want to block from your Contacts

Through the Google Messaging App

1. Open the Google Messaging app. Tap your profile picture in the top-right corner, then choose Spam & Blocked from the menu.
   This folder shows messages flagged as spam or from numbers you've blocked
2. Tap Block Numbers. To block a specific number, type it into the box and tap the plus (+) icon. To block everyone who isn’t in your contacts, turn on Block calls from unknown numbers.
   Check flagged messages in the Spam folder

How To Block Unknown Text Messages on iPhone

• Open Messages. Go to your iPhone’s home screen and tap the Messages app.
• Tap the unknown message. Find the message from the number you want to block and open the conversation.
• Tap the contact at the top. At the top of the screen, tap the number or name of the sender.
• Tap Info. On the menu that appears, tap Info to see more details about the sender.
• Select Block this Caller. Scroll down and tap Block this Caller, then confirm by tapping Block Contact. This stops the number from texting, calling, or FaceTiming you.
• Check your blocked list (optional). To see all blocked numbers, go to Settings > Phone > Blocked Contacts. You can add or remove numbers from there at any time.

How To Filter Spam Texts From Unknown Senders

Both Android and iPhone offer built-in features that filter out messages from unknown numbers and flag potential spam, so you only see the texts that matter.

Here’s how to use them:

Android

• Open Messages. Tap on the Messages app on your phone, then tap your Google profile icon in the top-right corner. Tap Message settings at the bottom of the menu.
  My Spam protection feature works very well to block unwanted messages
• Click General. In the settings menu, choose General, then scroll down and tap Protection and safety.
  Go through the General settings tab to manage spam protection and safety options
• Turn on Enable spam protection.
  This feature helps detect spam texts by using Google’s smart filtering — no message content is shared
• Check your spam folder. When spam protection is enabled, suspicious texts will be directed straight to the Spam & Blocked folder. You won’t receive alerts for them, but you can still open the folder at any time to review those messages.

iPhone

1. Open Settings. Go to your iPhone’s home screen and tap the Settings icon.
2. Tap Messages. Scroll down the menu and select Messages.
3. Turn on Filter Unknown Senders. Locate the Message Filtering section and enable Filter Unknown Senders.
4. Check your Messages app. After enabling the setting, your Messages app will display a new Unknown Senders tab. Any texts from numbers not in your contacts will go there automatically.

How To Block Unknown Messages Through Your Mobile Carrier

If you’re still receiving spam texts after blocking numbers on your phone, your carrier may be able to assist you. Most major mobile providers offer free tools to filter or block unwanted messages before they even reach your device.

Here’s what each major US carrier offers:

• Use the AT&T ActiveArmor app. It helps block suspected spam texts and lets you block numbers manually.
• Install Verizon Call Filter. It offers spam detection, text blocking, and custom filters.
• Use T-Mobile Scam Shield. It includes message filtering and number blocking.
• US Cellular, Boost, BT Mobile, and others also have similar features, just under different names.

If you get a suspicious message, forward it to 7726 (that’s “SPAM” on your keypad). Most carriers support this free service, which flags the message for review. You can also reply with STOP to opt out of promotional texts — but only do this with trusted businesses. Spammers often use responses to confirm that your number is active, which can exacerbate the issue.

If nothing else works, contact your carrier. They can apply extra filtering at the network level or escalate the issue if it’s part of a larger spam campaign.

Why Am I Getting Texts From Unknown Senders?

Most of the time, it's because your number was exposed or shared — either by accident, through a service you used, or by cybercriminals targeting large groups of phone numbers.

• Your number was leaked in a data breach. If your phone number was exposed in a data breach or sold by a shady website or app, it may have ended up on a spammer’s list. Once your number is out there, it can be shared across many marketing and scam networks.

• Sign-ups or forms you filled out. Sometimes, entering your number for a promo, contest, or online form permits companies to text you, even if the fine print wasn’t clear. These messages might come from unknown shortcodes or business numbers.

• Spammers are using random number generators. Scammers often use software that randomly generates phone numbers and sends out mass texts. They don’t know who you are — they’re just hoping someone replies or clicks a link.
• Spoofing or number masking. In some cases, the number you see isn’t the one that actually sent the text. Scammers can fake caller IDs to make the message appear to be coming from someone local or familiar — a tactic known as spoofing.
• You recycled an old phone number. If you've recently obtained a new number, you may be receiving texts intended for the previous owner. Many carriers recycle phone numbers, and it can take months for old accounts, alerts, or even spam to stop showing up.
• Your number is linked to a public profile. If your phone number is visible on your website, LinkedIn profile, resume, or social media, it can easily be scraped by bots and added to spam databases. Remove your number from public pages, or use a VoIP number, such as Google Voice, for public listings.

Common Types of Spam Text Messages

Scammers employ various tactics and messages to capture your attention. According to RoboKiller, people receive over 4.4 billion spam texts every week. That’s a considerable number, indicating how prevalent these messages are.

Here are some of the most common spam texts people get — and why you should never trust them:

• Fake delivery alerts. These texts pretend to be from USPS, FedEx, or DHL. They’ll say there’s a delivery issue and ask you to click a link. That link usually takes you to a fake website designed to steal your info.
• Banking or account warnings. You may receive a message indicating suspicious activity on your account. It often includes a link that asks you to “log in” and confirm details, but it’s a trap.
• “You’ve won” scams. Messages offering gift cards, prizes, or cash giveaways are almost always fake. Scammers use them to steal your info or install malware.
• Family or friend impersonation. Some spam texts claim to be from someone you know who lost their phone or needs urgent help. Don’t fall for it — always verify independently.
• Government-related scams. Scammers may claim to be from the IRS, Social Security, or the police. They’ll ask for payments or personal info. Real government agencies will never contact you by text like this.
• Payment failure notifications. These texts claim your Netflix, Amazon, or other subscription has failed and urge you to update your billing details. Real companies don’t use SMS for sensitive account info.
• Job offer scams. If it promises high pay for minimal work, especially via text, it’s likely a scam. Many of these schemes ask for upfront “application” or “training” fees.
• Two-factor authentication scams. Some attackers send fake security alerts or code requests. Never share your 2FA codes with anyone, even if the message seems legit.

How To Identify Spam Text Messages

If you're getting weird texts from unknown numbers, don’t assume they’re harmless. Spam messages can look convincing, but many are designed to steal your personal data or install malware. Here’s how to spot the warning signs before it’s too late:

• Check the sender’s number. If the number appears unusual, extremely short, or too similar to yours, it’s likely fake.
• Watch for urgent or threatening language. Messages saying “final warning” or “account closed” are trying to scare you. Don’t fall for it.
• Ignore messages offering rewards or refunds. If a random text says you won something, it’s likely a scam, especially if you never signed up for anything.
• Don’t trust requests for sensitive info. No honest company will ask for passwords, security codes, or bank details over text.
• Look for spelling and grammar mistakes. If the message is full of errors or just sounds off, it’s probably spam.
• Avoid tapping on unknown links. If the link appears suspicious or the sender is unknown, don’t click on it. It could be a trap.
• Be skeptical of generic greetings. Messages that start with “Dear user” or “Customer” instead of your name are usually not legitimate. Most real businesses personalize their communication.

Other Ways to Stop Unknown Text Messages

How can I prevent unwanted text messages? Blocking unknown SMS senders is a good first step. But spam often leaks through messaging apps, data leaks, and robocall databases. If you’re still getting texts from strangers, here are more ways to shut them down:

• Block callers in WhatsApp, Telegram, and other messaging apps. Scammers no longer rely solely on SMS. Many now use apps like WhatsApp, Telegram, or Signal to send phishing links or fake giveaways. Go to each app’s settings and manually block any number you don’t recognize.
• Use data removal tools. Your phone number might be exposed on data broker sites without your knowledge. Use services like Incogni or DeleteMe to help remove your personal data from these platforms, which cuts off spam at the source. These tools contact data brokers on your behalf and follow up if they don’t comply.
• Use an AI-powered call assistant. Tools like RoboKiller utilize AI to screen unknown calls and messages in real-time. They can automatically filter out robocalls and text scams by analyzing the caller’s behavior and language.
• Add your number to the Do Not Call Registry. If you're in the US, add your number to DoNotCall.gov. It won't block scammers (who don’t follow laws), but it will reduce the number of telemarketers that can contact you.

Tips To Stop Getting So Many Spam Messages From Strangers

If you’ve already tried blocking and deleting spam texts but they continue to arrive, it may be time to reassess your privacy habits. These quick tips will help you reduce unwanted messages, protect your number, and avoid getting flooded by strangers again.

• Use a VPN when browsing or signing up for services. Spam doesn’t always start with a message — sometimes it starts with your online activity being tracked. A reliable VPN hides your IP and encrypts your data, so websites and apps can’t easily track or sell your info, especially when you’re on public WiFi.
• Never respond to texts from strangers. Replying, even with “STOP”, tells scammers your number is active, which often leads to even more spam. If the sender is unknown, block the number and report it immediately.
• Keep your phone number private. Avoid sharing your number on public sites or social media. For sign-ups or apps you don’t fully trust, use a secondary number or a free virtual one instead.
• Review app permissions. Some apps can access your messages, contacts, or even your phone number. Go to your phone’s privacy settings and limit what each app can see. Only keep permissions on for apps you fully trust.

FAQs on Blocking Unknown Text Messages

How can I stop receiving text messages without blocking?

If you’re tired of getting texts but don’t want to block someone, you still have a few quiet ways to cut off the noise:

• Mute the conversation. Most messaging apps let you silence notifications from specific threads. You’ll still receive messages, but you won’t get alerts or sounds.
• Filter unknown senders. This moves texts from numbers not in your contacts into a separate tab without alerts.
• Use Do Not Disturb. Set up a custom mode that notifies you only through contacts or specific apps. Everything else, including unwanted texts, will be silenced.

Do I need to pay for the message-blocking services?

No. Most phones come with free built-in tools to block or filter unwanted texts. On both iPhone and Android, you can block numbers, silence unknown senders, and enable spam protection at no additional cost. Some carriers and third-party apps do offer premium spam-blocking features, but you don’t need to pay to stay protected. For most people, the free options are sufficient.

How often should I update my blocking settings?

It’s a good idea to review your blocking settings every few months, or anytime you notice more spam slipping through. Phone updates and app changes can sometimes reset filters or introduce new options you’ll want to enable. If you’ve recently switched devices, changed messaging apps, or started receiving more spam, check your settings immediately to ensure everything is still active. It only takes a minute, but it helps keep your inbox protected.

Can I block every text from people who are not in my contacts?

Sort of — but not completely. Most smartphones let you filter or silence messages from unknown senders, so they don’t appear in your primary inbox or trigger notifications. On iPhones, this means moving them to a separate tab. On Android, spam protection can flag and hide suspicious texts.

But you won’t be able to block every unknown number automatically — especially if it’s not flagged as spam. The best option is to enable all available filters and manually block any senders that slip through.

What to reply when someone unknown texts you?

The safest course of action is not to reply at all. Responding can confirm to scammers that your number is active, which often leads to even more spam. If the message appears suspicious, delete it immediately or report it as spam. If it seems like a legitimate caller, double-check the number first, but never share personal information until you’re certain who it is. When in doubt, silence is your best defense.

How to block messages from unknown numbers in Samsung?

Samsung phones make it easy to stop unknown numbers from messaging you — here’s how to do it:

• Open the Messages app, tap the three dots in the top-right corner, and go to Settings.
• Tap Block numbers and spam, then select Block numbers.
• Toggle on Block unknown callers — or enter a number manually and tap the plus (+) icon to block it.

Conclusion

You can’t stop every spam text from getting through, but you can make it a lot harder for scammers to reach you. Blocking unknown numbers, utilizing filtering tools, and being aware of potential threats will help you avoid most spam. And if you're already getting too many, don’t ignore it. Follow our guide and take control now before it gets worse.

References

1. https://www.robokiller.com/spam-text-insights
2. https://www.slicktext.com/blog/2022/10/17-spam-text-statisitics-for-2022/
3. https://www.ftc.gov/news-events/news/press-releases/2025/04/new-ftc-data-show-top-text-message-scams-2024-overall-losses-text-scams-hit-470-million
4. https://usafacts.org/articles/how-much-does-text-message-fraud-cost-americans/