Here’s how you can opt out of carriers’ ad programs, which run on your personal data

At Help Desk, we read privacy policies so you don’t have to. This week, a curious reader inspired us to dive deeper into cell carriers (thanks, Ron from Houston!). I read privacy policies from the three major wireless carriers — Verizon, AT&T and T-Mobile — and my eyeballs are only bleeding a little. All three carriers have some less-than-great privacy practices hiding in plain sight. Depending on the carrier, they can draw on your Internet history, app use, location and call history to learn things about you and nudge you to spend more money on products from themselves or third-party companies.

Some good news: You can opt out whenever you want, and we’re going to show you how.

Are there other privacy policies you want us to check? Send them our way at [email protected].

You agreed to what? Tax sites want your data for more than filing.

Verizon customers appear to be automatically opted into the company’s “Custom Experience” program, which means the company can use your browsing history and data from your apps to help target ads. The company says it “makes efforts” not to target you based on adult sites you visit, health conditions and sexual orientation. (Thanks, Verizon.) If you said “yes” to “Custom Experience Plus” at any point, the company can also use your location and call logs.

AT&T’s “Relevant Advertising” program works similarly. Customers are automatically opted in, and the company draws on information including your browsing history and videos you’ve watched to help show you targeted ads. If you sign up for “Enhanced Relevant Advertising,” your device location and call history are also fair game.

In comparison, T-Mobile’s data-crunching seems relatively tame: It says it doesn’t use any web-browsing, precise location or call history data for its ad program, but it can use your “mobile app usage” and video-viewing data, according to its website.

According to the companies, staying enrolled in these programs will improve your experience by showing you more relevant ads. (If targeted ads spark joy and you don’t mind your cell carrier using your information to make money, you can stop reading now and pour yourself a lemonade.)

But these programs may let not just cell carriers but also their third-party partners benefit from your personal data. T-Mobile, for example, states clearly in its privacy policy that it can share inferences based on your data with third parties. AT&T also leaves room in its policy to share your information, but a spokesman told me the company isn’t doing it (though it could theoretically start any time).

Verizon says that if you don’t opt out of Custom Experience, the company uses data including your Internet history to put you into interest categories like “sports lover.” A spokeswoman said the program doesn’t involve any third-party targeted advertising, but she wouldn’t tell me whether Verizon shares inferences with outside companies.

As always, it’s hard to know for sure where your information ends up. T-Mobile appears to be the only carrier of the three with a public list of its third-party partners.

You can opt out of these ad programs any time.

Verizon customers can opt out of Custom Experience by going to their privacy settings in the My Verizon app or by following this link. (While you’re there, check that you haven’t said yes to “Custom Experience Plus,” either.)

AT&T customers can opt out by signing into att.com, navigating to the “AT&T Consent Dashboard” and scrolling to the section “Control how we use your data.” (Or follow this link.) Opt out of “Relevant Advertising” and check that you’re not signed up for “Enhanced Relevant Advertising.”

T-Mobile says customers can opt out this way: In the app, go to More -> Advertising & Analytics -> Use my data to make ads more relevant to me. Turn the toggle off so that it turns gray. On the website, go to My Account -> Profile -> Privacy and Notifications -> Advertising & Analytics -> Use my data to make ads more relevant to me. Turn the toggle off.

(A caveat: Two of my Washington Post colleagues tried to opt out on T-Mobile accounts, and both got an error message saying it “looks like we got our wires crossed.” When they tried via the website, it froze or showed an error message. A T-Mobile spokeswoman said the company hadn’t heard of any problems but was working to address the issue.)

Keep in mind that opting out doesn’t necessarily stop carriers from collecting your data or marketing their own products to you.

Ask Help Desk: No, your phone isn’t listening to your conversations. Seriously.

I’d recommend opting out of all these personalized ad programs. It’s tough to determine exactly what information these companies are sharing with whom, and it’s shady for the companies to opt you in by default.

It’s going to be tempting for any company with as much data access as a cell carrier to make some money off your personal information. What matters is that customers are given clear descriptions of how our data is monetized — and that companies stop opting us in by default.