The initial call was placed using AT&T's networks in Midland, Texas, to mobile carrier Ratuken in Japan on an unmodified Samsung Galaxy S22 smartphone using AST SpaceMobile's BlueWalker 3 satellite.
AST SpaceMobile claims to be building "the first and only space-based cellular broadband network."
AT&T aims to use satellites to provide global cellular broadband from 2G to 5G.
In a press release, AST SpaceMobile, CEO and chairman Abel Avellan said: "While we take a moment to celebrate this tremendous accomplishment, we remain focused on the path ahead and pivotal next steps that get us closer to our goal of transforming the way the world connects."
It's unclear whether satellite access would come at an extra cost. In AT&T's original AST SpaceMobile partnership announcement, the company couldn't say whether existing plans would include satellite coverage.
While satellite offerings aren't available for consumers yet, this successful test brings widespread access one step closer to becoming a reality.