The fastest way to block unknown texts depends on your phone type

On iPhone, open any text from an unknown number, tap the sender's name at the top, then tap Block this Caller. On Android, the steps vary by manufacturer — Samsung phones let you long-press a message and select Block number, while Google Pixel phones have a Block option in the message details. Once blocked, that number cannot text you again, and the messages go to a separate folder you can ignore.

If you get texts from many different unknown numbers rather than repeat offenders, blocking one at a time is not practical. Both iPhone and Android let you filter unknown senders into a separate inbox instead, so legitimate contacts still reach you but spam stays out of your main thread list. This is often faster than blocking dozens of numbers.

Key Takeaways

  • iPhone users can block any sender by opening their message, tapping the name at the top, and selecting Block this Caller.
  • Android blocking steps differ by phone maker — check your phone's settings or long-press a message to find the block option.
  • Filtering unknown senders into a separate inbox works better than blocking if you receive spam from many different numbers.
  • Do not reply to or click links in texts from unknown numbers, even to ask them to stop — this confirms your number is active.
  • Your carrier may offer a spam-filtering service that catches many unwanted texts before they reach your phone.

How to filter unknown senders on iPhone

Go to Settings > Messages and turn on Filter Unknown Senders. This creates two tabs in your Messages app: one for people in your contacts, and one for everyone else. Texts from unknown numbers still arrive, but they go to the second tab and do not trigger notifications unless you have turned those on separately.

This approach keeps your main inbox clean without permanently blocking anyone. If a legitimate contact texts you from a new number, you will still see it — you just have to check the unknown senders tab. Many people find this less disruptive than blocking, because blocking is permanent until you manually unblock.

How to filter unknown senders on Android

The exact location depends on your phone maker. On Samsung devices, open Messages > Settings > Spam protection and turn on Filter unknown messages. On Google Pixel phones, go to Messages > Settings > Spam and abuse and enable Block spam. On other Android phones, check your default messaging app's settings menu — most have a spam or filtering section.

Once enabled, unknown texts go to a Spam or Blocked folder instead of your main inbox. You can review them later if needed, but they will not interrupt you with notifications. Like iPhone's filter, this is reversible — if you need to see messages from an unknown number, you can move them back to your main inbox.

When to block versus when to filter

Block a specific number if the same person or business keeps texting you after you have asked them to stop. Blocking is permanent and prevents that exact number from reaching you again. Use this for persistent harassers or numbers you are certain you never want to hear from.

Filter unknown senders if you get spam from many different numbers. Blocking each one individually would take hours and new numbers appear constantly. Filtering moves all unknown senders out of sight at once, which is faster and requires no maintenance. You can still check the filtered folder if you are expecting a text from someone new.

Why you should not reply to unknown texts

Replying to a text from an unknown number — even to say "stop texting me" — tells the sender that your number is active and monitored. Spam operations use this information to add you to more lists or sell your number to other spammers. The same applies to clicking links or calling back.

If a text claims to be from your bank, a delivery service, or another legitimate business, do not click the link in the message. Instead, open your phone's web browser, go directly to that company's official website, and log in from there. Scammers often send texts that look like they come from real companies but lead to fake login pages designed to steal your password.

Carrier-level spam filtering

Your phone company may offer a spam-filtering service that catches unwanted texts before they reach your phone. AT&T offers Call Protect, Verizon offers Call Filter, and T-Mobile offers Scam Shield. These services use databases of known spam numbers and filter them automatically. Some versions are free; others charge a monthly fee.

Check your carrier's website or call customer service to see what options are available on your plan. These services catch many spam texts that your phone's built-in filters might miss, because they work at the network level before the message reaches your device. Using both your phone's filter and your carrier's service gives you the most protection.

What to do if blocking is not enough

If you are receiving harassing texts from someone who keeps using new numbers to contact you, blocking and filtering alone may not stop it. Document the messages — take screenshots with dates and times — and report them to your carrier's abuse team. You can also report the harassment to the Federal Trade Commission at reportfraud.ftc.gov, which tracks patterns across many victims.

If the harassment is threatening or involves someone you know, contact local police and file a report. Provide them with the screenshots and any information you have about who is sending the messages. Police can sometimes work with your carrier to identify the sender's actual identity, even if they are using spoofed numbers.

Frequently Asked Questions

Can someone tell if I have blocked them?

Not directly. When you block someone on iPhone or Android, their texts simply fail to deliver, and they will not receive a notification that they are blocked. They may suspect it if their messages never get a response, but the phone does not tell them.

Will blocking delete messages I already received from that number?

No. Blocking only stops future messages from that number. Any texts you already received stay in your message thread unless you manually delete the conversation. You can delete the thread after blocking if you want it out of your phone.

What is the difference between blocking and filtering?

Blocking stops a specific number from reaching you entirely. Filtering moves messages from unknown numbers into a separate folder so you see them only if you check that folder. Filtering is easier if you get spam from many numbers; blocking works better for repeat offenders.

Do I need to pay for spam filtering?

Your phone's built-in filters are free. Your carrier's spam service may be free or cost a few dollars per month depending on your plan. Check with your carrier to see what is included with your current service.

Can spammers get around my block?

Spammers can use different numbers to contact you, which is why filtering unknown senders is often more practical than blocking. However, if the same number keeps texting you from a spoofed or changing number, report it to your carrier — they can block the source at the network level.