(SATURDAYS AND SUNDAYS The non-profit Oceanic Society takes all-day whale watching trips from San Francisco to the Farallones from May to November for $88 per person. (800) 326-7491; www.oceanicsociety.org.)

By BETH KOHN

SENTINEL CORRESPONDENT

Cheered on by a gleeful fanfare of harbor porpoises, our boat ducked under the awesome shadow of the Golden Gate Bridge. The morning was gray and still, the expectations palpable. Vigilant sightseers, preemptively clad in day-glo rubber rain gear, fidgeted with oversized binoculars, already on the lookout for leviathans.

Bay Area residents gaze off into the Pacific, smug in the knowledge that they’re standing at the end of the Western world. But about 30 miles offshore from San Francisco, the Farallon Islands win the distinction as the last local land mass on the continental shelf. An isolated wildlife refuge encompassing a handful of tiny guano-encrusted islands and a 150-year-old lighthouse, the massive bird colonies here stocked San Francisco markets with eggs during the latter half of the 19th century. Considered by some to be the Galapagos of the West Coast, the islets are crisscrossed by scores of migrating whales and great white sharks, as well as seals, sea lions and playful dolphins.

At just 120 acres, Southeast Farallon is the largest of the islands and the only one inhabited by people. A desolate granite mound iced white with bird droppings, the island is home to researchers from the Point Reyes Bird Observatory here to study seabirds, sharks and marine mammals. As our boat traced the shoreline from a respectful distance, a large male Steller sea lion lolled on a rock, framed by mysterious sea caves, malevolent crags and soaring arches. During the autumn, great white sharks feed on these blubbery beasts, the awesome attacks leaving startling slicks of red.

The sky was thick with flapping wings, leaving no doubt as to the dominant species on these inhospitable ocean pilings. The green carpet wrapping Tower Hill appeared speckled with pale rocks, but these were birds, thriving as freely as wildflowers in a spring field. The entire island is an openair rookery, home to pigeon guillemots, Brandts cormorants, Cassins and rhinoceros auklets, puffins and the ubiquitous common murres, and a cloud of western gulls shadowed our stern, acting out their favorite Hitchcock scene.

Unless you’re a biologist, the rugged dry land of the Farallones remains off-limits, but a small number of tours ferry landlubbers to the waters surrounding these jagged shipwreck-littered curiosities. Since the early 1980s, the non-profit Oceanic Society has worked to create public awareness about the wildlife teeming through the Farallones, and their naturalist-led excursions witness some of the most incredible whale watching anywhere.

Who knew that whales could breakdance? On the horizon, the silhouette of a graceful giant defied gravity, its entire body cresting upright above the waves in a wet pirouette. Juan Carlos Solis, our Oceanic Society naturalist and the manager of Public Programs at the California Academy of Sciences, seemed as giddy as the passengers lunging for their cameras. “I love the excitement of seeing the whales,” he enthused, of being able to witness an endangered species.

Then a throaty exhale reverberated nearby, and a fountain of spray erupted beside a lazy flotilla of murres. The beefy birds scattered in brief staggered spurts, furiously paddling on their bellies like wind-up bath toys. Silence. Everyone pitched toward the railings, scanning the waves with the breathlessness of psychics waiting in a haunted house. A minute later, another low moan hummed from the opposite side of the boat, followed by a glorious black flash of a car-length tail fluke.

For the next few hours, five majestic humpbacks, including a mother and calf, put on a daredevil show beyond imagination. They breached, they spy-hopped, they fluked and lob tailed all around us.

Translation: They kept leaping out of the water in new and inconceivable configurations. At the end of the day, we filed off the boat, dazzled and slightly damp, in thrall of these mighty monsters.

Contact Beth Kohn at fiercesf@igc.org.