The Channel Islands.

The self-guiding upper trail led us through an ice plant meadow to Pinniped Point, an outlook more than 200 feet above an epochal expanse of rugged bluffs, cavernous alcoves, and a tide pool fringed with lounging sea lions. I remembered the admonishments the guide from Island Packers Cruises had made to about 20 of us who came off the boat earlier that morning. She had told us to stay a body's length away from cliff edges; many of them were undercut and the soil rested on decomposing volcanic rock. "Otherwise you could end up in a Wile E. Coyote cartoon situation," she'd said, "where you look down and find yourself standing on air."

After the guide's 10-minute orientation on the landing cove dock, my friend Ben and I had gathered our gear, climbed 154 steps, hiked a half-mile, and pitched a two-tent camp for an overnighter atop East Anacapa, part of the Channel Islands National Marine Sanctuary and National Park, which celebrated its 25th anniversary last year. The barren seven-site campground on this island plateau was devoid of water, food, and electricity, offering nothing but his-and-hers pit toilets and a token picnic table where we'd dine. We'd carried all the necessities on our backs—30 pounds of supplies per frame pack, including two days worth of dried foods.

But roughing it was a no-brainer trade-off for incomparable kayaking and snorkeling in a Galàpagosian biosphere. Anacapa is the smallest of the Channel Islands, an archipelago of five islands born of volcanic exertion millions of years ago at the edge of the continental shelf. The island's five-mile stretch of rock is broken into three islets: East, Middle, and West. Anacapa is nearest the mainland, 12 miles southwest of Oxnard, where we had started our journey via an Island Packers's charter boat.

Trails and Tours

Our campsite secured, we devoured the upper trail that intersected the campground. The gum plant, Indian paintbrush, and giant coreopsis—native plants that lie dormant brown April through December—were blooming a riot of color when we visited in January. Merging onto the lower terrace, we passed a smattering of tile-roofed Mission Revival-style buildings erected in the 1920s to support the Coast Guard-built lighthouse that stands like an august picket on the east bluff. The central building houses the visitors' center. A churchlike structure protects two 55,000-gallon redwood water tanks. A stucco bungalow on lower ground is the home of National Park Service ranger Bill Struble.

The island's many elevations have a way of hiding other bipeds, so we were surprised to run into a huddle of day-trippers on the upper trail. They listened as volunteer naturalist Morgan Coffey explained how bootleggers reportedly had stashed liquor here during Prohibition. We bypassed the tour, eager to explore the island at water level. Ben had brought his ocean kayak. He'd been putting in long hours as a chemist for an environmental company, so his kayak hadn't been wet in a while. A second kayak wouldn't fit on my Jeep's roof for the drive from Orange County, so we'd decided to rotate excursions.

With the frame of an NFL tackle, Ben filled the narrow trail as he led the way a quarter-mile back to the landing cove platform. A brown pelican rose above the north face, caught updrafts and, with its seven-foot wingspan, settled into a pterodactyl-like glide. Cormorants, pigeon guillemots, and the elusive Xantus's murrelets are also among the seven species of seabirds that breed here.

Riding the Waves

Kayaking is an incomparable way to explore some of Anacapa's 130 sea caves, but it can be hazardous. Ranger Bill had cautioned us about 12-foot surges he'd seen earlier while on boat patrol. When it was my turn to kayak, I headed to the island's north side. Steep cliffs towered hundreds of feet above me; air pockets and lava tubes exposed by eons of wave erosion. I pointed into Cathedral Cove, listening to sea lion barks ricochet off a low cliff that sheltered a tide pool. Sea lion and harbor seal rookeries populate isolated beaches that provide sanctuary from sharks and humans.

As I coasted along the cliffs, waves within the bellies of caves made cataclysmic booms that sounded like distant ordnance explosions. A narrow cave begged me to enter, but as I watched a surge suddenly fill it I hit a hard reverse. It would have been too easy to get shanghaied by a rogue wave. Kayaking with such treachery always lurking made me realize what expert seamen the early Chumash must have been, navigating the Santa Barbara Channel in swift plank canoes. These seafaring Native Americans, who left behind 27 middens on Anacapa, were the original inhabitants of the northern Channel Islands 10,000 years ago.

On the way back, the sight of a harbor seal's flaccid body lifting and settling with the swells unnerved me. Dead, I thought, until it moved below the surface without a twitch, its compassionate eyes looking back at me as it floated in the opal blue before evaporating into shadow. I had caught it in a wave-lulled doze.

Beauty in the Beyond

Ben and I were the only campers on the island that night. Seated at the picnic table high above the Pacific, I gnawed on some high-energy jerky and traded with Ben for some Goldfish crackers. The foghorn's soothing intermittent moan resonated over the channel. I tucked into my one-man dome tent, head sticking out as if I were in an iron lung, so I could view a thousand stars undimmed by city lights. The wind spoke in whistling whispers.

The next morning I bee-lined down to the landing platform to work in some snorkeling. Ben was just departing on another kayaking odyssey, paddling east toward Arch Rock, a 40-foot natural bridge yawning above the sea. Kelp vines stroked me like clammy zombie arms as I kicked out of the landing cove, only to be assaulted by crosscurrents—akin to getting caught between the Butabi Brothers on the Roxbury dance floor. I swam around to the north side, dropped my mask into place, and dove.

The beauty shocked a grin onto my face. I observed some blacksmith and a vivid orange garibaldi sauntering between waving strands of kelp. Golden fingers of sunlight reached through 80 feet of mesmeric visibility, creating a stained-glass effect. It was holy down here, like an underwater cathedral. Giant kelp forests abound in these waters, encircling the islands and sheltering more than 1,000 species of marine life, including bat rays, migrating blue whales, leopard sharks and moray eels.

A blue shark cruised into view about 40 feet directly below me, the size of a pectoral-finned bowling pin at this distance. I paced it, but the muscular tail lazily propelled it much faster than I could swim. The shark moved on, driving deep into the kelp bed. The gelid water made me regret not bringing a wetsuit, forcing me to swim back before hypothermia woodened my muscles.

Ben returned from his expedition and we climbed up to camp for a pseudo-lunch of energy bars and sports drinks. We struck camp in time to meet Island Packers's 64-foot twin diesel, Vanguard, at the landing platform, where 25-odd day-trippers waited. Three campers jumped off as the trawler-style vessel backed against the platform.

We took seats inside her salon to ease the sea's misty chill on the return crossing. Maybe one nautical mile passed before the diesel hum crooned Ben's head down to the booth table. He looked like an overgrown school-kid napping at his desk. Poor guy can't handle an outdoors expedition, I thought. My next memory was of waking up—mouth agape, head lolled sideways against the seatback as if my neck had been snapped—at the captain's loudspeaker announcement to prepare for disembarkation.

Learn more about Channel Islands National Park by calling 805-658-5730 or visiting www.nps.gov/chis.

Plan your own Anacapa Adventure

By Sea

Island Packers Cruises: Anacapa-bound boats depart from Channel Islands Harbor. An island tour guide accompanies the cruise and the captain offers information about marine life during the hour-long crossing. The boat makes detours if whales or dolphins are about. Hot drinks and snacks are available onboard. Rates: Day trips, $42; campers, $54; kayaks, $12 or $18 depending on kayak length. (805) 642-1393; www.islandpackers.com.

Channel Islands Kayak Center: Kayak rentals include paddles, life vests, and helmets. Staff members provide a safety orientation and help load kayaks and gear onto the boat. Rates: single kayaks cost $25 for the first day, then $20 per day; double kayaks are $35 for the first day, then $30 per day. (805) 984-5995; www.cikayak.com.

Pacific Scuba & Snorkel: wetsuit, hood, boots, gloves, mask, snorkel, fins, and bag are included in snorkel rental. Rates: One day, $40; two days, $55. (805) 984-2566; www.pacificscuba.com.

By Land

National Park Service: Visitors should reserve boat transportation before making a reservation for wilderness-style camping on East Anacapa Island. There are 154 stairsteps from the boat landing to the island (pictured), which has two acres of hiking area. An extra day's supplies are recommended in case foul weather delays the boat. More camping information is available at www.nps.gov/chis/camping.htm. Campers should check in with the park ranger or Island Packers guide upon arrival. Rates: $10 per night (maximum stay is seven days). (800) 365-2267; http://reservations.nps.gov.

By the Shore

Embassy Suites Mandalay Beach Resort: Serenity gardens, waterfalls, and lagoons provide a taste of the tropics in Oxnard. Ocean views are plentiful. Rates: $239-$359. (805) 984-2500; www.mandalaybeach.embsuites.com.

Country Inn & Suites Port Hueneme: Cozy, oversized guest rooms are two blocks from Hueneme Beach. An overnight stay for two includes two tickets for a half-day whale-watching cruise. Rates: $119-$149. (805) 986-5353; www.countryinns.com/porthuenemeca.

C.J. Bahnsen is a freelance writer based out of Orange County, California.