The basic steps differ by phone type, but all phones let you block senders

You can block text messages on any smartphone — iPhone, Android, or older phones — by adding a number to your phone's block list. The blocked person can still send you messages, but you won't see them arrive, and they won't get a notification that you blocked them. The message straightforward disappears from your inbox.

The exact steps depend on what kind of phone you have. On an iPhone, you open the message thread, tap the sender's name at the top, scroll down, and tap "Block this Caller". On Android, you open the message thread, tap the three dots in the corner, and select "Block" or "Block number" — the exact wording varies by phone maker and Android version. On older phones without smartphones, you usually access a block list through Settings or a Messages menu, though the option may not exist on very old devices.

Blocking works at the phone level, not through your carrier or messaging app. That means if someone texts you through your phone's default SMS app, blocking them stops those texts. If they message you through WhatsApp or another app, you need to block them separately within that app.

Key Takeaways

  • Blocking a number on your phone prevents their text messages from appearing in your inbox, but they won't know they're blocked.
  • iPhone users tap the sender's name and select "Block this Caller"; Android users tap the three dots and select "Block".
  • Blocking works only for the app or service where you block — blocking someone in SMS doesn't block them on WhatsApp or Facebook Messenger.
  • You can unblock a number at any time by going back to your block list and removing it.

How to block on iPhone

Open the Messages app and find the conversation with the person you want to block. Tap their name or number at the very top of the thread — you'll see it in a gray bar above the message history. A menu will open showing their contact card.

Scroll down to the bottom of that card until you see "Block this Caller" in red text. Tap it. A confirmation message will appear asking "Block 'Name'?" — tap "Block Contact" to confirm. The conversation will remain in your Messages app, but no new messages from that number will come through.

If you want to unblock them later, go back to that same conversation, tap their name at the top, scroll down, and tap "Unblock this Caller".

How to block on Android

Open your default messaging app — usually called Messages, SMS, or Messaging depending on your phone maker. Find the conversation with the person you want to block and tap and hold on it until it's highlighted. A menu will appear at the top or bottom of the screen.

Look for an icon that looks like a circle with a slash through it, or tap the three vertical dots (called a menu button) in the corner. Select "Block" or "Block number" from the options. Some Android phones also let you tap the sender's name or number within the conversation and select "Block" from there. A confirmation message will appear — tap "Block" or "OK" to confirm.

To unblock someone on Android, go to your Messages app settings, look for "Blocked numbers" or "Blocked contacts", find the number you want to unblock, and tap the minus sign or delete option next to it.

Blocking within messaging apps like WhatsApp, Signal, or Telegram

If someone messages you through an app rather than through regular text, you need to block them inside that app. Blocking them on your phone's SMS list won't stop their messages in WhatsApp or Signal.

In WhatsApp, open the conversation, tap the person's name at the top, scroll down, and tap "Block Contact". In Signal, tap and hold the conversation, tap the three dots, and select "Block". In Telegram, swipe left on the conversation (iPhone) or tap and hold it (Android), then tap "Block User". Each app stores its own block list separately from your phone's block list.

What happens when you block someone

When you block a number, the sender can still send you messages — they just won't reach you. They won't receive a notification saying "this person blocked you". Their message will straightforward fail to deliver or appear to deliver normally, depending on the service. This is different from muting a conversation, where you still receive messages but don't get notifications about them.

The blocked person cannot call you either, though again they won't be told why the call didn't go through. If they try to call, it will ring once or go straight to voicemail depending on your phone and carrier.

Blocking is not the same as reporting spam. If you report a number as spam to your carrier, they may investigate it and take action against the sender. Blocking only affects your own phone.

When blocking doesn't stop all messages

Blocking works well for one person, but it has limits. If someone is determined to contact you, they can use a different phone number or create a new account on a messaging app. Blocking is a friction tool — it stops casual contact but not someone who is actively trying to reach you through multiple numbers.

If you're receiving repeated messages from different numbers that appear to be from the same person or organization, you may be dealing with spam or harassment that goes beyond what blocking can handle. In that case, you can report the numbers to your carrier, file a complaint with the Federal Communications Commission (FCC) if it's spam, or contact local law enforcement if it's harassment or threats.

Blocking vs. other ways to manage unwanted messages

Blocking is the strongest option, but you have other choices depending on what you want. Muting a conversation silences notifications but leaves the messages in your inbox — useful if you want to ignore someone without fully cutting them off. Marking messages as spam or junk trains your phone's filter to catch similar messages in the future, but the messages still arrive first.

Some carriers offer spam-filtering services you can turn on in your phone's settings or through your carrier's app. These filter out likely spam before it reaches you, though they sometimes catch legitimate messages by mistake. You can usually review filtered messages in a spam folder before deleting them.

Frequently Asked Questions

Can someone tell if I blocked them?

No. They won't receive a notification. Their messages will either fail to send or appear to send normally, depending on the service. They might suspect you blocked them if you stop responding, but the phone won't tell them directly.

If I block someone and then unblock them, can they see old messages?

No. The messages you received before blocking them stay in your inbox. When you unblock them, they can send you new messages, but they cannot see what you did or didn't receive while they were blocked.

Do I need to block someone on my carrier's network, or just on my phone?

Blocking on your phone is enough. You don't need to contact your carrier. Your carrier's spam filter is separate and works automatically in the background — you can turn it on or off in your phone settings, but it's not the same as blocking an individual number.

What if I block someone by accident?

You can unblock them when ready. On iPhone, go back to the conversation and tap their name, then tap "Unblock this Caller". On Android, go to your Messages app settings, find "Blocked numbers", and remove them from the list. They'll be able to contact you again right away.

Can I block a number that hasn't texted me yet?

On most phones, you can add a number to your block list manually without waiting for them to contact you first. On iPhone, open Contacts, find the person, tap their name, scroll down, and tap "Block this Caller". On Android, open your Messages app, go to settings, find "Blocked numbers", and add the number manually. This is useful if you know a number you want to avoid.