Apra Harbor is a deep-water port on the western side of Guam in the Mariana Islands. It serves both as a U.S. Navy station and a commercial port.

The harbour is formed by Orote Peninsula to the south, and Cabras Island in the north. To the south the harbor narrows and then widens again to form an inner harbor. The southern end of the harbor is the U.S. naval station, while the northern end is the commercial port.