Mobile data is the lifeblood of the digital out of home (DOOH) ad market. And T-Mobile sees an opportunity to infuse the market with better targeting data and, eventually, new measurement capabilities.
T-Mobile Advertising Solutions announced Monday that its mobile data is now exclusively available for out-of-home (OOH) campaign targeting via Vistar Media, the OOH ad platform that T-Mobile acquired in January 2025.
Advertisers can now use Vistar to activate both off-the-shelf and custom audiences built on T-Mobile’s first-party data insights.
These insights include not just the mobile location data that helps OOH ad networks determine how many impressions their inventory gets. It also includes anonymized data on which apps T-Mobile users have installed on their phones and how often they use them – which are valuable signals for building target audiences.
With that data now integrated into Vistar’s platform, advertisers can bring the targeting capabilities they’ve used for in-app campaigns to the OOH channel, said Hannah Grobmyer, VP of client solutions at ad agency Kepler, which has been testing the integration.
Bringing app data to DOOH
Many of Kepler’s clients use in-app signals as either the primary signal – or a strong proxy signal – for measuring and driving business activity, customer retention and new audience conquesting, Grobmyer said.
For instance, DTC brands use those app insights to determine how successful new product launches are when advertised in ecommerce apps, she said. But they can also gain insight into which ecommerce app users are buying competitor brands, she said, and then target those in-market users to grow their audience share.
Now, those brands can target those audiences not just with in-app ads and online display, Grobmyer said, but also on OOH screens that might be close to retail locations or along the route of their daily commutes.
T-Mobile and other cellular service providers are in a unique position when it comes to providing that app-based targeting data, particularly for OOH campaigns.
Every time you use a mobile app that’s connected to the internet, it requires access to your cellular provider’s mobile network or a Wi-Fi network. So T-Mobile gets insight into what’s happening on a user’s phone whenever their device pings its network or the internet, said Jess Zhu, head of advertising products and development, at T-Mobile Advertising Solutions.
T-Mobile can examine those network requests to determine which apps the user is using and how often they access those apps, Zhu said. It can then use that information to package the user into a target audience that can be reached via Vistar’s OOH platform.
Say, for instance, a user regularly opens up the Chewy pet food delivery app and the Friskies Cat Fishing app – which is a game designed for cats that lets them swipe at moving images of fish on their human’s phone. That data could be used to bucket the user into a “cat lovers” audience, Zhu said.
And, if the user has opted into location tracking, T-Mobile can also tell whether that user comes into proximity with an OOH ad. It can then use that exposure data to facilitate retargeting that user on other media channels.
However, because of tightening regulations around location data and the use of mobile device IDs for ad targeting, T-Mobile couldn’t share this data with just any third-party ad platform, Zhu said. Hence the reason why it’s making this data exclusive to Vistar, a company it owns, for OOH ad targeting.
It’s a similar arrangement to how T-Mobile makes its data exclusively available for omnichannel ad campaigns via Blis, an omnichannel DSP it also acquired in 2025, she said.
Audience building
Although T-Mobile is just now announcing the exclusive availability of its data for OOH campaigns in Vistar, the companies have been testing using T-Mobile’s data to build bespoke audiences for select advertisers since last year, Zhu said.
Kepler, due to a yearslong partnership with Vistar that extends back before the company was acquired by T-Mobile, participated in some early tests, Grobmyer said. For instance, it was able to build custom audiences that incorporated a brand’s conquesting and upselling goals directly into the targeting.
Now, T-Mobile and Vistar are rolling out a more scaled offering that includes off-the-shelf audiences as well as the opportunity to continue building bespoke audiences.
“Vistar is creating these segments on our behalf,” Grobmyer said. The agency can bring Vistar a campaign brief, and whether through the platform’s user interface or in meetings with account reps, Kepler gets recommendations for off-the-shelf audiences, custom opportunities or a mix of both, depending on the campaign strategy, she said.
Plus, Zhu said that T-Mobile is in the early phase of experimenting with new agentic AI solutions and other self-serve tools that help advertisers build custom audiences or find new off-the-shelf audiences that can be incremental to their targeting.
“I would call them prototypes or proofs of concept; they’re not fully available to users yet in the UI,” Zhu said. “That’s probably something we’ll have readily available closer to the first half [of next year].”
T-Mobile also sees opportunity to use its data to offer new measurement capabilities for DOOH advertisers. Although the company doesn’t have a DOOH measurement offering now, “that is on our road map to look into for next year,” Zhu said.
Making DOOH more programmatic
And, when it comes to DOOH, T-Mobile sees a lot of green field, Zhu said, and it’s hoping its new targeting and, eventually, measurement capabilities will bring bigger ad budgets to the channel.
“Digital out of home is different from the more entrenched desktop display or OLV markets mostly because it doesn’t have as good measurement or targeting already,” she said. “Being able to marry that online and on-device engagement with physical movement, that’s uniquely relevant to digital out-of-home, because it’s missing some of those gimmies like cookie tracking.”
From Kepler’s perspective, T-Mobile’s data being available within an OOH platform it owns gives the agency more assurance about the fidelity of the targeting.
“Our expectation is that as we continue to test these segments, they will drive higher lift because they’re going to be more closely aligned with the places and spaces that we know our audiences are in,” Grobmyer said.
And, while many of Kepler’s clients tend to activate OOH campaigns using a mix of programmatic and direct buying strategies today, Grobmyer sees that data fidelity giving clients more confidence to scale up their programmatic OOH media buying.
Some clients might even be more willing to target OOH inventory beyond the big-ticket outdoor screens in highly in-demand locations, which usually require direct deals, she said. It could also help clients who want to know the exact cross street where their OOH ads are running get comfortable with a less micromanaged approach.
Now, Kepler can demonstrate “the relative scale and affordability compared to what they’re used to,” she said. “Like, ‘Look how many more millions of eyes you’re going to get versus that massive billboard in the middle of Penn Station.’”
