There are no large trees or shrubs on San Miguel Island. With the episodic cycles of droughts, overgrazing and soil stripping this island has experienced, along with wind and water erosion, this island's vegetation has been severely affected in the past.

Beach and coastal dune vegetation are well developed on this island. Coastal bluff, coastal sage scrub, grassland and coastal salt marsh communities occur here as well. About 220 different plants are found on San Miguel Island, including natives, island endemics and introduced plants. Although there are no plants at the species level endemic to this island, a species of buckwheat (Eriogonum grande dunklei) is known only from this island.

San Miguel Island supports six species of pinnipeds, more than anywhere in the North Pacific. They included the California sea lion (Zalophus californianus), Norther nseal lion (Eumetopias jubatus), Northern fur seal (Callorhinus ursinus), Guadalupe fur seal (Artocephalus townsendi), Northern elephant seal (Mirounga angustirostris), and harbor seal (Phoca vitulina).At certain times of the year, the Point Bennett area has in excess of 10,000 animals which can be heard and smelled for miles. It is the most outstanding display of wildlife found anywhere on the Southern California Islands.