In 1980, Congress designated Anacapa, San Miguel, Santa Barbara, Santa Cruz and Santa Rosa Islands and 125,000 acres of submerged lands as a national park because they possess unique natural and cultural resources. The park provided habitat for marine life ranging from microscopic plankton to the Earth's largest creatures, the blue whale.

Seafaring Indians plied the Santa Barbara Channel in swift, seaworthy canoes called "tomols". The Chumash or "island people" had villages on the northern islands and traded with the mainland Indians. The Gabrielino people lived on the southern island of Santa Barbara. 1542 found the explorer Juan Rodriguez Cabrillo entering the Santa Barbara Channel. Cabrillo, commanding an expedition in service of Spain, was the first European to land on the islands. While on his northbound odyssey of exploration, Cabrillo wintered on an island he called San Lucas (San Miguel or possibly Santa Rosa Island). He died as a result of a fall on that island and may have been buried on one of the Channel Islands, but his grave has never been found. Subsequent explorers included Sebastian Vizacaino, Gaspar de Portola and English Captain George Vancouver, who in 1793, fixed the present names of the islands on nautical charts. Beginning in late 1700s and into the 1800s, Russian, British and American fur traders searched the islands' coves and shorelines for sea otter. The otter was almost hunted to extinction. The hunters then turned toward the seals and sea lions. Several of these species faced extinction as well. In the early 1800s, the Chumash and Gabrielino people were removed from the islands and settled in mainland missions. Hunters, settlers and ranchers soon came to the islands. By the mid-1800s, except for fishermen, ranching became the economic mainstay. In the early 1900s, the US Lighthouse Service (later the US Cost Guard) began its stay on Anacapa Island. The US Navy took control over the Island of San Miguel just before World War II.

In 1938, President Franklin D. Roosevelt proclaimed the islands of Anacapa and Santa Barbara a national monument. On March 05, 1980, President Jimmy Carter signed into law a bill abolishing Channel Islands National Monument. He then raised the status of these islands, with the addition of the waters surrounding Santa Cruz and Santa Rosa to that of a national park. This area was augmented by the designation of Channel Islands National Marine Sanctuary later that year. The sanctuary boundaries stretched six miles offshore, encircling Santa Barbara and the four northern islands, including their interconnecting channels. Today, Channel Islands National Park is part of the International Man and the Biosphere program to conserve genetic diversity and an environmental baseline for research and monitoring throughout the world.

Visitors to the park may enjoy a variety of recreational opportunities, such as SCUBA diving, snorkeling, swimming, bird watching, kayaking, whale watching, and sailing. On the islands, one may camp, hike, picnic, and explore tidepools, isolated beaches, and rugged canyons. Park naturalists conduct interpretive hikes on the islands throughout the year.

Annual visitation to the park's mainland visitor center is 120,000. Visitation to the islands and waters is low, with about 30,000 visitors traveling to the islands, and another 60,000 who go only into park waters. Although most visitation occurs in the summer, migrating gray whales and spectacular wildflower displays attract visitors in the winter and spring. Autumn is an excellent time to travel to the park, as well as for diving, as the days are usually sunny, with minimal winds and clear ocean water.

The Mainland Visitor Center features a museum, living tidepool exhibit, three-dimensional models of all the park islands, interactive touch-screen exhibit, a tower with telescopes for viewing the islands, picnic area overlooking the Ventura Harbor, a bookstore, and an outdoor native plant garden. Visitors will enjoy the 25-minute park movie, "A Treasure in the Sea", throughout the day in the auditorium. Every Saturday and Sunday park rangers present free interpretive programs on the natural and cultural resources of the park. Throughout the week, other programs and school visits may be scheduled by calling the visitor center. All facilities are fully accessible.