The Best Ways to Block Robocalls

Unwanted calls declined further in August as carriers roll out blocking technology

Illustration of a call coming into a call phone from a robot Illustration: iStock

The pandemic has had an impact on a great many things in the past year, including the volume of robocalls. Believe it or not, they’re actually on the decline, helped by the effects of COVID-19 shutdowns, new call-filtering technology, and recent efforts to promote the implementation of that technology.

But consumers can still take extra steps to make sure they’re getting as few unwanted calls as possible. 

In August the number of robocalls received in the U.S. dropped by 4.4 percent from the previous month, according to the blocking and tracking service YouMail. And yet, on average this year, U.S. consumers have received 4.3 billion unwanted calls a month.

"We’ve now seen the second straight month with a decline in robocalls since the STIR/SHAKEN rollout on June 30th," says YouMail CEO Alex Quilici. "However, the volume of calls is still within the general range it’s been at all year, so illegal robocallers clearly haven’t given up in their attempts to reach consumers."

More on Robocalls

STIR/SHAKEN technology is designed to identify spoofed calls, which use a fake number to trick you into answering your phone. 

By June 30, a deadline imposed by the TRACED Act, all carriers had to certify in a Federal Communications Commission database that they had begun implementing the technology across their networks.

And, according to the database, 4,798 companies say they have implemented it (at least in part) and are now using anti-robocall technology. AT&T, T-Mobile, and Verizon said Wednesday that their wireless networks are all 100 percent compliant with STIR/SHAKEN. However, some smaller service providers have yet to introduce it.

And so, as of this week, the FCC began prohibiting providers from accepting calls that originate on a network that has not certified its implementation of STIR/SHAKEN in the commission’s database or explained in detail the steps it has taken to ensure it is not the source of robocall traffic.

“The FCC is using every tool we can to combat malicious robocalls and spoofing—from substantial fines on bad actors to policy changes to technical innovations like STIR/SHAKEN,” says Acting Chairwoman Jessica Rosenworcel. “Today’s deadline establishes a very powerful tool for blocking unlawful robocalls.”

Lavinia Kennedy, director of product management at Transaction Network Services (TNS), says a vast majority of bad robocalls—95 percent—originate on small networks and not the large Tier 1 carriers AT&T, T-Mobile, and Verizon, according to the company’s research. Kennedy says the implementation of STIR/SHAKEN in tandem with the use of additional call-filtering apps by subscribers has led to the small percentage of high-risk robocalls in Tier 1 networks.

While the industry and government continue working to solve the robocall problem, here are some things you can do to block robocalls yourself.

Optimize Your Phone to Block Robocalls

Many cell phones offer a “whitelisting” tool that will allow calls only from numbers in your contact list.

But there’s a downside. It also blocks calls from people you may want to talk to, like a doctor or delivery person, who aren’t in your contacts. That means you have to either update your contact list or briefly turn off the tool when there’s an important call you don’t want to miss.

Here’s how to install the whitelist tool.

For iPhones (iOS 13 and later): To turn on Silence Unknown Callers, go to Settings > Phone, then scroll down, tap Silence Unknown Callers, and turn on the feature. Calls from unknown numbers are silenced and sent to your voicemail, and will appear in your recent calls list.

For Android phones: To turn on Block Calls From Unidentified Callers, tap the phone icon usually found at the bottom of your home screen, then at the top right corner of the screen, tap the three dots > Settings > Blocked Numbers. Enable Block Calls From Unidentified Callers by tapping the toggle switch on the right.

Google’s Pixel phones: These smartphones have a tool called Call Screen that’s built in and works automatically. When you receive a call from any number, you can tap Screen Call on your home screen and Google Assistant will answer it for you and ask the caller to identify himself or herself and the reason for calling. When a caller responds, a real-time transcript of the response is displayed.

If it’s someone you want to speak to, you can simply answer the call. If it’s a robocall, you can automatically report it to Google as spam as well as log it or blacklist it locally on your device. The tool will then block the number from calling you in the future. Note, though, that while this tool (and others like it) screens the call, it doesn’t prevent the phone from ringing and interrupting you.

Use Your Carrier’s Anti-Robocall Tools

Last year big phone carriers like AT&T, T-Mobile, and Verizon installed STIR/SHAKEN call-filtering technology that recognizes most legitimate phone numbers while weeding out or warning about suspicious numbers.

Carriers can also block suspect calls under the new TRACED Act that took effect last year. 

For the most part, consumers don’t have to do anything to get these free services to work. Calls recognized as legitimate will be allowed through with an indication, such as a green check mark. Numbers not recognized as legit will either be blocked or allowed to ring with an alert indicating that the call is suspected to be spam or a scam.

But these services might not be automatically enabled for all phones on all carriers. You may have to activate the basic robocall blocking features on your phone. The steps (listed below) vary depending on the carrier.

Note that customers of smaller carriers, such as rural phone service providers, might not have access to these services yet, because many of these carriers are still implementing STIR/SHAKEN technology.


AT&T offers Call Protect, which will display a “V” (for verified) on your caller ID for calls considered legitimate. It will also block potentially fraudulent calls by giving a busy signal. You’ll still get spam calls, but your caller ID will display Suspected Spam and a category like Political, Nonprofit, Telemarketer, Survey, or Robocaller.

How to Turn on Call Protect
On the web, go to your myAT&T account overview. Find the My Digital Phone section and choose Check or Manage Voicemail & Features > Phone Features > Call Protect, then follow the prompts to turn on Call Protect.


T-Mobile offers two free anti-robocall tools: Scam ID and Scam Block. Scam ID identifies and tags suspicious calls. T-Mobile One customers automatically get Scam ID. Other customers can activate it free. Scam Block is a more robust free tool, which, as the name implies, blocks calls before they ring. But customers need to activate this service.

How to Turn on Scam ID
Dial #ONI# (#664#), then press the call button.

How to Turn on Scam Block
Dial #ONB# (#662#), then press the call button.


Verizon automatically enrolls eligible customers in the free version of Call Filter, which detects spam and blocks high-risk calls. This option is available on a wide variety of phones. See the full list of compatible devices.

Verizon also offers a more robust paid anti-robocall tool called Call Filter Plus, which can block unwanted calls. It costs $3 per month per line for up to two lines. It’s $8 per month for three or more lines. Most Verizon phones come preloaded with the Call Filter app, which is necessary to activate Call Filter Plus. If your phone isn’t preloaded with the app, it’s available for download at the app store.

How to Activate Call Filter Plus

Android: Open Call Filter app, then tap Account > Subscription Status > Subscribe Now.

iPhone: Open Call Filter app, then tap Get Call Filter > Subscribe.

Online: Go to your account’s My Verizon section. Go to the Add-ons and apps page in My Verizon and select Manage Call Filter > Manage Add-on. Select which line you want to manage, and select the Call Filter Plus bubble under Choose Your Call Filter product. Choose whether to apply Call Filter to all eligible lines or choose Selected lines. You can get Call Filter Plus (Multiline) for accounts with three or more eligible lines for $8 per month per account. Click Continue > Confirm when the Confirmation screen appears.

My Verizon App: Open the My Verizon app. Tap the menu in the top left > Plans & Devices, then scroll down and tap Explore Add-ons. Scroll down to find Call Filter and tap Learn More, then choose a line to manage and tap Enroll > Call Filter Plus > Next. To sign up for Call Filter Plus (Single line), tap the $2.99/mo. per line Call Filter Plus option. To sign up for Call Filter Plus (Multiline) (requires three or more eligible lines), tap the $7.99/mo. for three or more lines Call Filter Plus option. Review your changes and tap “I accept the Terms & Conditions,” then tap Confirm.

Add More Robocall Protection

Downloading a third-party call-blocking app or signing up for your phone company’s separate robocall blocking service could provide even more protection.

Some of these apps charge a fee, and others offer a free subscription. But some “free” apps are free only for an introductory period and will automatically begin charging you a fee unless you cancel your subscription before the free trial ends.

These beefed-up services use algorithms, lists of blacklisted numbers, and proprietary technology to filter out suspicious calls and can supplement the call-blocking and labeling functionality of STIR/SHAKEN. They also give you more control to manually choose which calls can come through and which ones to block.

But you should consider potential privacy implications before downloading third-party apps, warns Maureen Mahoney, a policy analyst at Consumer Reports.

“There are few restrictions on what these companies can do with your data, so keep in mind that you’re trusting developers with sensitive information about your calls,” she says.

For even more privacy protection, there are premium services that offer tools such as access to a virtual private network (VPN) that can safeguard your data on public WiFi networks. 

Editor’s Note: This article has been updated to include the May data on robocalls and how carriers are responding to the June 30 deadline for STIR/SHAKEN technology.

Image of Octavio Blanco, editor at CR with Money CIA

Octavio Blanco

My mission: To write stories that broaden readers' horizons and offer new solutions they can apply to their lives. Who I write for: My family, my friends, my neighbors, myself, and—most important—you. My passions: Music, art, coffee, cheese, good TV, and riding my electric bike (for now). Find me on Twitter: @octavionyc