Santa Barbara Island was named by Sebastian Vizcaina, who arrived here on 04 December 1602. This date is known as Santa Barbara's Day. Because of the lack of fresh water, Native Americans did not reside on the island, but they stopped off on journeys to other islands. Not until the 20th century was Santa Barbara Island settled to any extent. During the 1920s, farming, grazing, intentional burning by island residents and the introduction of rabbits severely damaged the native vegetation. During World War II the U.S. Navy used the island as an early warning outpost. Through non-native grasses including oats, barley, and brome dominate the landscape, with protection and encouragement the native vegetation is recovering. With the rabbits now removed, stands of giant coreopsis thrive. In places this sunflower grows up to ten feet tall. In the spring, gold fields blanket the island with tiny, bright yellow flowers.

California sea lions and, in winter, elephant seals breed here. Bird watching is superb. Western gulls, xantus murrelets and brown pelicans nest on the island plateaus and cliffs. Land birds, including barn owls, American kestrels, horned tarks and meadowlarks nest here. Although not commonly seen, the island deer mouse and the island night lizard, a threatened species, live on the island.

Santa Barbara Island offers 5.5 miles of trails to explore. A good place to start is the Canyon View self-guiding nature trail near the ranger station and campground. A trail booklet explains the island's interesting features. A park ranger stationed on the island interprets its features and enforces rules and regulations. There is no telephone, but in emergencies the ranger has radio communications with park headquarters.