The simplest way to block unknown texts

Most phones let you block texts from unknown senders directly in your messaging app, without downloading anything extra. On iPhone, open the message from the unknown number, tap the info icon (circle with an i), scroll down, and select "Block this Caller." On Android, open the message, tap the three dots at the top, and choose "Block & report spam." The blocked sender cannot text you again, and their messages will not appear in your inbox.

If you get texts from many different unknown numbers rather than one repeated sender, blocking one at a time becomes tedious. That is when filtering tools built into your phone become more useful than blocking individual numbers.

Key Takeaways

  • iPhone and Android both have built-in blocking features in the Messages app that work without extra software.
  • Filtering unknown senders (available on both phones) automatically sorts texts from numbers not in your contacts into a separate folder, reducing what you see without deleting messages.
  • Reporting spam to your carrier — AT&T, Verizon, T-Mobile, or others — helps them identify patterns and block sources for all customers.
  • Third-party apps like TrueCaller or RoboKiller can filter more aggressively but require you to grant them access to your contacts and message history.
  • No filter catches everything, so staying cautious about links and requests in unexpected texts remains your strongest defense.

Using your phone's built-in filters for unknown senders

Rather than blocking individual numbers, you can filter unknown senders into a separate folder. On iPhone, go to Settings > Messages, scroll down, and turn on "Filter Unknown Senders." Texts from people not in your contacts will move to a separate tab labeled "Unknown Senders" in your Messages app. You can still read them if you want, but they will not interrupt your main conversation list or trigger notifications.

On Android, the process depends on your phone model and which messaging app you use. If you use Google Messages (the default on most newer Android phones), open the app, tap your profile icon at the top right, go to Settings > Spam and abuse, and turn on "Enable spam protection." This filters suspected spam into a "Spam & abuse" folder. If you use Samsung Messages on a Galaxy phone, open Settings within the app, find "Spam," and enable "Spam filter."

Filtering is gentler than blocking because it keeps the messages on your phone — you can still read them if you realize one is legitimate — but removes them from your daily view. This matters if you are waiting for a text from a business that might use an unfamiliar number, like a delivery service or a doctor's office.

Reporting spam to your phone carrier

Your carrier — AT&T, Verizon, T-Mobile, or another provider — has its own spam-blocking tools that work across their network. When you report a spam text to your carrier, you are giving them data about which numbers are sending unwanted messages. If many customers report the same number, the carrier can block it for everyone.

To report spam, contact your carrier directly. AT&T customers can forward spam texts to 7726 (SPAM). Verizon customers can use the "Report Junk" button in their Messages app or forward to 7726. T-Mobile customers can report through the Messages app or forward to 7726. Other carriers have similar systems — check your carrier's website for the exact method. Reporting takes a minute and costs nothing.

Carrier-level blocking is not perfect. Spammers change numbers frequently, and some legitimate businesses use shared numbers that might look suspicious. But reporting still matters because it gives carriers the information they need to identify patterns and block sources before they reach other people.

When to use third-party filtering apps

Apps like TrueCaller, RoboKiller, and Nomorobo offer more aggressive filtering than your phone's built-in tools. They maintain databases of known spam and scam numbers, and some use artificial intelligence to identify patterns in incoming texts. If you receive dozens of spam texts per day, one of these apps might reduce the noise significantly.

The trade-off is access. These apps need permission to read your contacts, your message history, and sometimes your location data to work effectively. TrueCaller, for example, builds a searchable database of phone numbers and names — if you use it, your own number and contact information may appear in their database and be searchable by other users. RoboKiller analyzes your incoming calls and texts to improve its filtering, which means your message patterns are sent to their servers.

If you decide to use a third-party app, read its privacy policy before installing it. Look for what data it collects, how long it keeps that data, and whether it shares information with other companies. A free app often makes money by selling insights about user behavior, so understand what you are trading for the filtering service.

What blocking and filtering cannot do

No filter catches every spam text, and some legitimate messages may be blocked by mistake. Filtering is a reduction in noise, not a complete solution. A text from an unknown number that passes through your filters can still contain a phishing link or a request for personal information — the fact that it was not flagged as spam does not mean it is safe.

Scammers also change tactics constantly. They spoof numbers (making their text appear to come from a local number or a business you recognize), use new sending methods, and craft messages designed to look urgent or official. A filter trained on yesterday's spam patterns may not catch today's new approach.

This is why blocking and filtering work best as one part of a larger habit: do not click links in unexpected texts, do not reply to requests for personal information, and do not assume a text is legitimate just because it looks official or comes from a number that seems local.

Blocking texts on older phones or basic models

If you use an older iPhone (iOS 13 or earlier) or an older Android phone, your built-in filtering options may be limited. On very old iPhones, you can still block individual numbers through the Messages app, but the "Filter Unknown Senders" feature may not exist. On older Android phones, the spam-filtering options depend on which version of Android you have and which messaging app came with your phone.

If your phone does not have built-in filtering, your best options are blocking individual numbers as they arrive, reporting spam to your carrier, or switching to a third-party messaging app that includes filtering. Some carriers also offer spam-blocking services you can turn on through your account settings or by calling customer service — ask your carrier what options are available to you.

If you are considering a new phone partly because of spam texts, know that newer phones have better filtering built in. iPhone 14 and later, and most Android phones from the last two years, have more sophisticated spam detection than older models.

Frequently Asked Questions

If I block someone, can they still see that I blocked them?

No. When you block a number on iPhone or Android, the sender will not receive a notification that they were blocked. Their text will straightforward fail to deliver, and they may see a delivery error or no message at all. They cannot tell the difference between a blocked number and a number that is turned off.

Will blocking a number stop them from calling me too?

On both iPhone and Android, blocking a number blocks both texts and calls from that sender. If you want to block only texts but still receive calls from a number, you will need to use a third-party app — your phone's built-in blocking is all-or-nothing.

What should I do if a scam text includes a link that looks like it's from my bank?

Do not click the link. Instead, open your banking app directly (not through the link) or call the number on the back of your card to verify whether the message is real. Banks and legitimate businesses will never ask you to click a link in a text to verify your account or password. If the text is fake, report it as spam and block the number.

Can I block all texts from unknown numbers at once?

Your phone's filtering feature (Filter Unknown Senders on iPhone, spam protection on Android) does this automatically — it sorts texts from unknown numbers into a separate folder rather than blocking them entirely. If you want to block all unknown numbers completely, you would need a third-party app, though this may also block legitimate texts from businesses you do not have saved in your contacts.

Does reporting spam to my carrier actually work?

Yes, but slowly. When many people report the same number, carriers can identify patterns and block that source. However, spammers change numbers frequently, so reporting one number may not stop the texts when ready. Reporting still matters because it gives carriers data to identify larger patterns and block sources before they reach other customers.