Shamelessly copying from
Wikipedia:
The Municipal Ferry Building was built in 1941 as a Works Project Administration (WPA) project, built at Berth 84. It was designed in the Streamline Moderne style by architect Derwood Lydell Irvin of the Los Angeles Harbor Department. It has a five-story octagonal clock tower. Its "sister ferry terminal" was across the main channel at Berth 234, also Irvin designed in the Streamline Moderne and built by the WPA in 1941.
It was a working ferry terminal from 1941 to 1963, for the ferry connecting San Pedro and Terminal Island in the Los Angeles Harbor. During those years, the double-decked ferries "Islander" and "Ace" transported thousands of passengers and automobiles to and from the tuna canneries, docks, shipyards, and military bases on Terminal Island.
In 1963, the Vincent Thomas Bridge was completed, connecting mainland San Pedro to Terminal Island, and the ferry service became obsolete. The ferry service was terminated on 14 November, and the bridge opened on 15 November.
The San Pedro terminal building was used for many years as an office building by the Los Angeles Harbor Department. The ferry terminal building on the Terminal Island side was demolished in 1972 to expand cargo operations.