Google has launched a service called YouTube Kids, a new version of the internet’s leading destination for video aimed squarely at children.

Unveiled today in a blog post, the service is available as a free app on iOS and Android, and at the moment, it can only be accessed within the U.S.

“[YouTube Kids is] the first Google product built from the ground up with the little ones in mind," Shimrit Ben-Yair, YouTube Kids group product manager, said in the post. “The app makes it safer and easier for children to find videos on topics they want to explore.”

YouTube Kids limits the world of content on the service to curated, family-friendly videos, channels, and educational clips, and includes such titles asThomas the Tank Engine, Reading Rainbow, andNational Geographic Kids. To reel in its target audience, the app’s interface features large images, colorful icons and carefully curated launch videos on the main homepage. There are four sections---Shows, Music, Learning and Explore---to explore within the app, and it also includes features like timer settings and a search function.

The company says search gives users access to YouTube’s main database of videos, but that YouTube Kids’ results are automatically filtered for safe content. The service also gives adults a range of parental controls, including the ability to disable search completely, limit screen time and cap the volume. Google has disabled comments on the service, but it does show some kid-friendly ads.

For Google, entering the children’s market is a move that has been a long time coming.In December, the company announced its intentions to create products for kids 12 and under, and now, it seems, the company is making good on that promise.

Recently, new data has been showing how quickly children are moving from watching TV to consuming internet videos:According to recent reports from research outfit Neilsen, television watching in the home has declined in the last three years in the 2- to 11-year-old age group, down from 110.3 hours per month in 2011 to 102.9 hours in 2014. Conversely, in the same age group, internet video watching has increased by 87 percent to 6.3 hours a month in 2014.

Other players have already dipped their toes into the space, notably Amazon, which hasfor years included child-friendly content as part of its subscription service offerings. But Google has the advantage of being the internet’s most popular destination for video content by far.

Some analysts estimate its valuation, even independent of Google, to beas much as $40 billion, and it’s already secured awell-established viewer base among teens. If YouTube can earn the trust of parents and hook a new group at an even earlier age, then that’s tapping a whole new market of users that will literally grow up with the service---and use it for a much longer portion of their lives.