Blocking a number on a landline depends on what your phone company offers
Most landline providers offer call blocking through their network, meaning the block happens before the call reaches your phone — you won't hear it ring. The exact steps depend on whether your provider is a major carrier like Verizon, AT&T, or CenturyLink, or a smaller regional company. Some landlines also have built-in blocking features on the phone itself if you have a digital phone system.
The fastest way to find out what you have is to call your landline provider's customer service number (it's on your bill) and ask: "Do you offer call blocking, and how do I set it up?" They can tell you immediately whether it's free, costs a few dollars per month, or comes with your current plan. Many providers include basic blocking at no extra charge.
If your provider doesn't offer network-level blocking, or if you want an immediate solution while you wait for them to set it up, you can also use a call-blocking device that plugs into your phone line.
Key Takeaways
- Call blocking on a landline usually happens at your phone company's network, so blocked calls never reach your phone.
- Most major carriers offer free or low-cost blocking, but you have to call them to turn it on — it is not automatic.
- You can block a specific number by calling your provider with the number you want blocked, or through their online account portal if they have one.
- If your provider does not offer blocking, a plug-in call-blocking device can intercept unwanted calls before they ring your phone.
- Some digital phone systems built into modern landline phones have their own blocking features that work independently of your provider.
How to block a number through your phone company
Call your landline provider's customer service line and tell them you want to block a specific number. Have the unwanted number ready. The representative will add it to your account, and the block usually takes effect within a few hours. Some providers let you block up to 10 or 20 numbers for free; others charge per number or offer an unlimited plan for a monthly fee.
If your provider has an online account portal (Verizon, AT&T, and CenturyLink all do), you may be able to add blocked numbers yourself without calling. Log into your account, look for a section called "Call Blocking," "Call Management," or "Preferences," and follow the prompts to enter the number. The exact name and location of this feature varies by provider.
Write down which numbers you have blocked and keep that list somewhere safe. If you ever want to unblock a number, you will need to contact your provider again or go back into your online account to remove it.
Using a call-blocking device if your provider does not offer the service
If your landline provider does not have call blocking, or if you want to block calls immediately while waiting for them to set it up, you can buy a standalone call-blocking device. These plug into the phone jack between your wall outlet and your phone. Popular options include the CPF3000 (made by Clarity) and the Nomorobo device, which cost between $40 and $80 one time with no monthly fee.
These devices work by checking incoming calls against a database of known spam and unwanted numbers. When a blocked number tries to call, the device stops the call before it reaches your phone. Some devices also let you manually add numbers to a personal block list. You do not need to call your phone company or change your service — the device handles everything on its own.
The downside is that you have to buy the device upfront, and you are responsible for keeping it powered on. If the power goes out, the device stops working until power returns. Most devices also require occasional updates to their spam database, though many update automatically if you connect them to the internet through a separate adapter.
Blocking calls on a digital landline phone system
If you have a modern digital phone system (sometimes called a VoIP landline or digital phone service), your phone itself may have built-in call blocking. Check your phone's manual or look for a menu button on the handset. Some digital phones have a "Block" or "Reject" option that you can access by pressing a button during an incoming call, or through a settings menu.
To block a number this way, you usually press a button to view the incoming call details, then select "Block This Number" or similar. The phone stores the blocked number in its memory. The next time that number calls, the phone either sends it straight to voicemail or displays a message that the call is blocked.
This method only works if you are home to answer or see the call. It does not prevent the call from ringing your phone the first time, and it does not block the number across all your devices — only on that specific phone. For these reasons, network-level blocking through your provider is usually more effective.
What to do if the same number keeps calling after you have blocked it
Spammers and scammers sometimes use different numbers to get around blocks. If you block a number and then get calls from similar numbers (same area code, same first few digits), the calls are likely coming from the same source using a spoofing service. Blocking each number individually will not solve the problem.
In this case, ask your provider whether they offer a spam-filtering service that blocks entire ranges of numbers or uses caller ID patterns to catch spoofed calls. Verizon Call Filter, AT&T Call Protect, and CenturyLink Secure Calling are examples. These services cost a few dollars per month but are much more effective against organized spam campaigns.
If the calls are harassing or threatening, you can also file a complaint with the Federal Trade Commission at reportfraud.ftc.gov. Keep a record of the dates and times of the calls, and note whether the caller left a message. This information helps the FTC track down the source.
Blocking numbers when you do not know who is calling
If you are getting calls from unknown numbers and want to block them all at once, most providers offer a "Block All Unknown Callers" or "Block Anonymous Calls" setting. This stops calls from numbers that do not display caller ID information. However, it also blocks legitimate callers who have their caller ID blocked for privacy reasons, such as some hospitals, government offices, and businesses.
Before you turn on this setting, consider whether you are expecting any calls from organizations that might have blocked caller ID. If you are, you may want to stick with blocking individual numbers instead. You can always turn the setting off later if you realize you are missing important calls.
To enable this feature, call your provider or log into your online account and look for "Block Anonymous," "Block Restricted," or "Block Private Calls." The exact wording depends on your provider.
Frequently Asked Questions
Does blocking a number on my landline stop text messages from that number?
Landline blocking only stops phone calls, not text messages. Landlines do not receive texts in the traditional sense, but if you have a digital phone service that includes texting, you may need to block the number separately in that service's settings or through a different app.
Can I block a number if I do not know the full phone number?
No. Your provider needs the complete phone number to block it. If you only have a partial number or a name, ask your provider whether they can look it up in their system. Some providers can help if you remember the area code or approximate time of the call.
What happens if I block a number by mistake?
You can unblock it by calling your provider or logging back into your online account and removing the number from your blocked list. This usually takes effect within a few hours. Keep a list of blocked numbers so you know what you have blocked and can unblock it if needed.
Will blocking a number on my landline also block it on my cell phone?
No. Landline blocking and cell phone blocking are separate. You have to block the number on each device or service individually. If you want to block a number on both, you will need to set it up through your cell phone provider as well.
Is there a charge for call blocking on a landline?
Most major carriers include basic call blocking for free or charge a small monthly fee (usually $3 to $5) for unlimited blocking. Some offer a limited number of free blocks per month and charge for additional ones. Call your provider to find out what is included with your plan.