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

Most phones let you block a number directly from the text message itself — no settings menu needed. Open the message, tap the number or sender name, and look for a block or report option. On iPhone, this appears as "Block this Caller" or "Report as Junk". On Android, you'll see "Block number" or "Block & report spam". The blocked sender can still send messages, but they won't reach your phone or trigger notifications.

If you want to block multiple numbers at once, or if a spam sender keeps switching numbers, your phone's built-in spam filter is more effective. Both iPhone and Android have filters that catch common spam patterns without you having to identify each sender. These filters learn over time and improve as you report messages.

For persistent spam from unknown numbers, a third-party app can catch more than your phone's default tools. Apps like TrueCaller, RoboKiller, or your carrier's spam-blocking service (AT&T Call Protect, Verizon Call Filter, T-Mobile Scam Shield) use databases of known spam numbers and block them before the message reaches you.

Key Takeaways

  • You can block a single number by opening the message, tapping the sender, and selecting "Block" — this takes 10 seconds and stops that number from reaching you.
  • Your phone's built-in spam filter (iPhone's Filter Unknown Senders, Android's Spam Protection) catches patterns of spam without you naming each sender.
  • Turning on your carrier's spam-blocking service (AT&T Call Protect, Verizon Call Filter, T-Mobile Scam Shield) adds a second layer and is usually free or low-cost.
  • Third-party apps like TrueCaller or RoboKiller use larger spam databases but require you to grant them access to your messages and contacts.

How to block a single number on iPhone

Open the Messages app and find the text from the sender you want to block. Press and hold the message thread (the conversation, not just one message). A menu will appear with options including "Block this Caller" or a three-dot menu with more choices. Tap "Block this Caller".

If you've already deleted the message, go to Settings > Messages > Unknown & Spam and tap "Filter Unknown Senders" to turn it on. This won't block a specific number, but it will move texts from people not in your contacts into a separate tab so they don't clutter your main inbox.

Once you block a number, that sender's messages won't appear in your inbox, and they won't trigger notifications. You can see a list of all blocked contacts in Settings > Phone > Blocked Contacts, and unblock anyone from that list if you change your mind.

How to block a single number on Android

Open the Messages app (or whatever texting app came with your phone — Samsung uses Samsung Messages, Google Pixel uses Google Messages). Find the conversation with the sender you want to block. Press and hold the conversation thread until a menu appears, then tap "Block" or "Block number".

Some Android phones will also ask if you want to "Report as spam" at the same time. Reporting helps your carrier's spam filter learn which numbers are spam, so other people get blocked too. You can do both — block the number and report it.

To see your blocked numbers, go to Settings > Apps > Messages > Blocked contacts (the exact path varies by phone brand). You can unblock anyone from this list.

Turning on your phone's built-in spam filter

On iPhone: Go to Settings > Messages and turn on "Filter Unknown Senders". This moves texts from people not in your contacts into a separate "Unknown Senders" tab. You won't get notifications for these messages, so spam won't interrupt you. The filter doesn't block the messages — they still arrive, just in a quieter place.

On Android: Open your Messages app and go to Settings > Spam protection (or Advanced > Spam protection, depending on your phone). Turn on "Enable spam protection" or "Spam detection". Google Messages and Samsung Messages both have this built in. The filter learns as you report spam, so it gets better over time.

These built-in filters catch common patterns — messages with suspicious links, messages from numbers that have been reported by many users, messages with phishing language. They're not perfect, but they catch the majority of obvious spam without you having to act.

Using your carrier's spam-blocking service

Your phone company offers its own spam filter on top of what your phone does. AT&T Call Protect, Verizon Call Filter, and T-Mobile Scam Shield are free or cost a few dollars per month. These services block calls and texts before they reach your phone, using databases of known spam numbers that are much larger than what your phone stores locally.

To turn on your carrier's service, call customer service or log into your account online. Most carriers let you enable it in seconds. Once it's on, spam texts are blocked at the network level — they never reach your phone at all, so you don't see them in a separate folder. You also won't get notifications.

The trade-off is that carrier services sometimes block legitimate messages by mistake, especially if you're expecting a text from a business number or automated service. If you're not getting a text you're expecting, check your carrier's blocked list or turn off the filter temporarily.

When to use a third-party spam app

Apps like TrueCaller, RoboKiller, and Nomorobo use crowdsourced spam databases — they know which numbers thousands of people have reported as spam. These apps can catch spam that your phone's filter misses because they have access to a much larger list of known bad numbers.

The downside is that third-party apps need permission to read your messages and contacts. Before you install one, check what permissions it's asking for. If an app wants access to your location, photos, or calendar, that's a sign it's collecting more data than it needs for spam blocking.

Start with your phone's built-in filter and your carrier's service. If you're still getting a lot of spam after both are on, then consider a third-party app. Most people find that the combination of iPhone's "Filter Unknown Senders" plus their carrier's service, or Android's spam protection plus their carrier's service, blocks 80 to 90 percent of spam.

What to do if spam keeps coming from different numbers

Spammers sometimes use a new number for each message to get around blocks. If you're getting spam from many different numbers, blocking them one at a time won't help. Instead, rely on your spam filter and carrier service to catch the patterns.

Report every spam message you get. When you report a message as spam, you're teaching your phone's filter and your carrier's filter which patterns to watch for. After you report 5 to 10 messages, your filter usually learns the pattern and starts catching similar messages automatically.

If the spam is coming from a specific business or service (a fake delivery notification, a fake bank alert), don't reply and don't click any links. These messages often use legitimate-looking sender names to trick you. Block the number, report it as spam, and move on.

Frequently Asked Questions

Can a blocked sender tell that I blocked them?

No. When you block a number, the sender can still send messages, but they won't know whether you blocked them, deleted their messages, or straightforward didn't see them. Their message goes into the void from their perspective — no delivery confirmation, no read receipt.

Will blocking a number stop them from calling me too?

Yes. Blocking a number blocks both texts and calls from that sender. If you want to block only texts but still receive calls, you'll need a third-party app — your phone's built-in block feature blocks both.

What's the difference between blocking and reporting as spam?

Blocking stops that specific number from reaching you. Reporting as spam tells your carrier and your phone's filter that the number is spam, so the filter learns to catch similar messages from other numbers. You can do both at the same time.

If I block someone, can they still leave me a voicemail?

On iPhone, blocked callers cannot leave voicemails. On Android, it depends on your phone brand and carrier — some allow blocked voicemails to go to a separate folder, others block them entirely. Check your voicemail settings to see what your phone does.

Do I need to pay for spam blocking?

Your phone's built-in filter is free. Your carrier's spam-blocking service is usually free, though some carriers charge a few dollars per month for premium versions. Third-party apps vary — some are free with ads, some charge a subscription. Start with what's free on your phone and carrier before paying for an app.