The two-stage Falcon 9 rocket lifted off from coastal Vandenberg Space Force Base at 4:41 a.m. and arced over the Pacific.
The Falcon's first stage returned and landed on a SpaceX droneship in the ocean. It was the 11th launch and recovery of the stage.
The second stage continued into orbit and deployment of the satellites was confirmed, said launch commentator Youmei Zhou at SpaceX headquarters in Hawthorne, California.
Starlink is a satellite-based global internet system that SpaceX has been building for years to bring internet access to underserved areas of the world.
Saturday's mission was the 34th launch for Starlink, a constellation of nearly 2,000 satellites in low Earth orbit.