‘A good port and a good land’--and a good time to be had by all.

When Juan Rodriguez Cabrillo and his crew sailed into what is now San Pedro Harbor on Oct. 8, 1542, they saw “a good port and a good land,” according to the explorers’ log.

Nearly 4 1/2 centuries later, weekend explorers young and old can discover all that plus a good time in San Pedro this Saturday at the Cabrillo Marine Museum’s fifth annual Autumn Sea Fair.

“The fair is a celebration of the ocean environment,” said Larry Fukuhara, the museum’s program director. “It’s a very nice setting and it’s a chance to have a lot of fun and learn a little bit.”

Admission is free. Parking at the museum is $5.50, but free parking and shuttle bus service will be available at the parking lot at 22nd and Miner streets.

The fair, which runs from 10 a.m. to 4 p.m., begins the museum’s yearlong 10th anniversary celebration of its modern facility, designed by Frank Gehry, at 3720 Stephen White Drive.

“The old museum was a bathhouse years ago,” recalled Bee Powell, a museum volunteer. “That was when the old red streetcars used to run down to the beach. John Olguin started the museum in the abandoned building on the beach.”

Olguin, director emeritus of the museum, and Susanne Lawrenz-Miller, the current director, will talk about how the new museum, its programs and research projects have grown over the last 10 years.

The festivities will include contests, games and music. A living sand sculpture contest encourages people to be part of their own beach art. “You might have a sculpture of a dolphin with a child riding its back, or a giant clam with someone inside,” Powell said.

The sea monster contest offers a chance to turn imagination into reality with costumes or models. “Everyone secretly thinks that there are monsters in the sea,” Fukuhara said. Prizes will be awarded in both contests. Entry forms must be submitted to the museum by today.

At about 1 p.m., Sam Hinton, a folk singer and marine biologist, will sing “Whaling Ditty” and other sea songs and tell nautical tales on the museum’s lawn. Fair patrons may bring a lunch and picnic on the lawn under the trees or buy food and beverages provided by Canetti’s Restaurant, Buscemi’s Pizza and other local restaurants.

Later in the day, there will be more music courtesy of the Black Label String Band, a country and Western group, Jeff Agisim, a singer of sea chanteys, and Harold Green, who plays the “Chapman stick,” an instrument that looks like the fret board of a guitar and produces bass and treble sounds, Fukuhara said.

A water show featuring the Ralph J. Scott, a 65-year-old Los Angeles city fireboat, begins at 2:30.

Other attractions include a treasure hunt with the “Swashbuckling Pirates,” a man-made camp forest, arts and crafts, a Baja whale-watch slide show and the museum’s regular exhibits.

“We have the largest collection of Southern California saltwater animals in the world,” Fukuhara said. The museum has 35 aquariums, a touch tank and simulated tide pool with sea urchins, starfish and sea anemones, a 25-foot skeleton of a gray whale, and models of a killer whale and a hammerhead shark.

The fair is sponsored by the museum’s volunteers, the Los Angeles Department of Recreation and Parks and the Port of Los Angeles.

Representatives from the National Audubon Society, Heal the Bay, the New West Fish and Wildlife Service, the National Marine Fishery, the Los Angeles Harbor Department and other groups will be available to answer questions about marine life, conservation and future plans for the Port of Los Angeles.

“When people, especially kids, go to the beach, they see the ocean, but they don’t always make the connection with the animals that live in the ocean,” Fukuhara said. “We hope we can teach the young ones that what they’re looking at is not just water, but a total environment.

“And sometimes, the kids can influence and change their parents’ way of thinking.”

What: Cabrillo Marine Museum’s fifth annual Autumn Sea Fair.

Where: 3720 Stephen White Drive, San Pedro. Free parking and shuttle service at 22nd and Miner streets.

When: Saturday, 10 a.m.-4 p.m.

Admission: Free.

Information: Call 548-5762.