From 1942 until 1982, the island was the site of the Coast Guard's recruiting training center (boot camp), enlisting and training hundreds of thousands of coast guardsmen including many of the 214,239 who served in the Pacific and European Theaters of World War II.

The island houses a number of U.S. Coast Guard commands and its facilities are managed by Base Alameda.

Area commands include: It is also the homeport for four Legend-class cutters: Coast Guard Island also houses and supports a number of other Coast Guard commands with detachments or regional offices located on the island, including: Coast Guard Electronic Support Unit (ESU) Alameda and Naval Engineering Support Unit (NESU) Alameda were also located on the island until those units were decommissioned in 2013.

Improvements were started at that time and by 1933 included streets, utilities, spur tracks, a trestle bridge from Oakland, a transformer station, and rebuilding of the existing wharves.

The cost was more than one and a half million dollars and provided facilities for Base 11 and the Coast Guard Store (warehouses).

The first contract provided for five barracks, mess hall and galley, engineering and administration buildings, an infirmary, roadways, heating, plumbing, electrical and fire protection.

Specialty training was added later to include fireman, signalman, laundryman, radioman, boatswain's mate, cooks and bakers, and port security.