The park's fleet of historic vessels is its centerpiece. The Balclutha, built in Glasgow and launched in 1886, carried grain from California to Europe around Cape Horn and later worked as a salmon packet in Alaska. The C.A. Thayer, an 1895 schooner, hauled lumber along the Pacific coast. The Eureka, a walking-beam side-wheel ferry built in 1890, carried passengers and vehicles across the bay before the bridges were built. The Hercules is a 1907 ocean-going steam tug. The SS Jeremiah O'Brien, a World War II Liberty ship, is moored nearby at Pier 45. And the USS Pampanito, a World War II submarine, sits at the adjacent pier, open for visitors to climb through its cramped interior.

The park's maritime museum occupies the streamline moderne building at the foot of Polk Street, originally built in 1939 as a public bathhouse and later converted to museum use. Inside, exhibits cover the maritime history of the Pacific Coast from indigenous seafaring through the Gold Rush, the age of sail, the whaling era, World War II, and the modern shipping industry. The building's Art Deco murals, created by WPA artists, are worth the visit on their own. The park's research library, housed in a separate facility, contains one of the most important collections of Pacific maritime documents, photographs, and ship plans in the country.

The park brings its history to life through hands-on programs. Visitors can board the vessels, climb below decks, and experience the conditions that sailors, fishermen, and ferry passengers endured. Volunteer docents, many of them former mariners, share stories that connect the physical reality of the ships to the human experiences they carried. On certain weekends, the C.A. Thayer's rigging is demonstrated by volunteers who climb the masts and handle the lines. The park is a reminder that San Francisco was, before it was anything else, a port city -- its wealth, its diversity, and its culture all arrived by water, on ships very much like the ones still tied to the Hyde Street Pier.