THE PAYOFF CAME QUICKLY. Within four minutes of starting my ascent of the steep path at the north end of the Big Island’s Waipio Valley, its mile-long black-sand beach came back into view. I had just walked the length of that very strand, where I’d passed a trio of the 60 or so feral horses that live in the valley. From my well-earned perch, I watched waves break along the shore, which was framed by 1,000- and 2,000-foot cliffs, while the vividly green valley that stretched 6 miles into the Kohala Mountains looked like a colossal spirulina-and-kale smoothie pouring into the ocean.

I’d had a taste of the Big Island’s wild green immensity on an earlier trip when, like most visitors to the island, I stood at the Waipio Valley Lookout after arriving by car. That visit had whetted my appetite for today’s breathtaking backpacking trip. And breathtaking is exactly what I mean. The huffing had already started.

Home of Hawaiian royalty until the 1600s (and sometimes called the Valley of the Kings), Waipio was a fertile settlement of a few hundred until a 1946 tsunami drove most of the inhabitants away. Today, only a few dozen farmers and fishermen remain.

Waipio Valley is home to some 60 wild horses, descendants of those that were used by farmers in the area. Photo: Andrew Richard Hara

The single road down, with its at times 40% incline and deeply rutted bottom, is only open to cars with four-wheel drive, but the valley isn’t completely isolated. So my goal was to go beyond it, climbing the 1,200-foot cliff to its north and then hiking up and down the 12 gulches crisscrossing the Kohala Forest Reserve’s Muliwai Trail until I reached the next valley, Waimanu, which is fronted by its own dazzling beach. No road accesses that destination, so with any luck I would have the whole place to myself.

While tourists on the island’s resort-dominated Kohala Coast were paying $500 a night or more to exercise their legs inside air-conditioned gyms, I registered online for one of the Waimanu Valley’s nine campsites for $18 a night, and trusted my trekking poles, calves and thighs to get my 25-pound pack and me where we needed to go.

Unsure whether I could manage the hike alone and certain it would be more fun with a buddy, I enlisted my friend Jason Cohn to join me on the adventure. He grew up on the island, and his family runs a Big Island outfitter called Hawaii Forest & Trail. I figured he would know which streams were safe to filter water from and the names of a few local plants. It only took him a day to say yes. I celebrated by splurging on a needlessly heavy tin of teriyaki Spam and some locally smoked marlin jerky for our three-day trip. He celebrated by packing whiskey.

The distance from the Waipio Lookout, where we began our hike, to the Waimanu campground is less than 10 miles. But very, very little of the route is flat.

Crossing the Waimanu Stream at the end of the Muliwai Trail. Photo: Jason Cohn

It took us 20 minutes to climb the first 400 feet of the trail, and another half-hour to reach the top of the cliff, where we left the coast and entered an ever-changing canopy. Along the way, we nibbled on the cobalt flowers of chest-high blue porterweed plants, which tasted just like shiitake mushrooms. Jason pointed out flora as if he were identifying plantings in his backyard and then scampered along like a local mouflon sheep.

Although the trail is minimally maintained, with four emergency helipads and a shelter along the way, the only real signs of human presence were white and orange signs before each gulch, warning of the chance of flash floods, falling rocks and hazardous cliffs.

The postings seemed less like warnings and more like simple declarations that, some days, that’s just how it is. But we negotiated the gulches easily enough, relying on our poles whenever we had to hop from stone to stone or navigate up or down a particularly steep section. Where the streams were deep, I switched to water shoes. Jason went barefoot.

The Hamakua Coast, where gulches as well as mountains separate seven valleys, each with its own beach. Photo: Andrew Richard Hara

Occasionally, the inviting blue of the ocean peeked through the trees, but mostly the forest itself held our attention. Guava trees lined the slopes, and their swollen, round yellow fruits littered the trail, scenting the air with a fragrance that was alternately musky and floral. We saw orchids and coffee trees; the lacy green fronds of hapuu tree ferns that measured more than a dozen feet tall and wide; paper-bark eucalyptuses that slough sheets of bark from their trunks and exposed roots; and sprawling hau trees—hibiscuses from which ancient Hawaiians made canoes, cordage and even hula skirts.

Six hours after setting out we reached the final cliff. A sign said the Waimanu Valley was 0.90 miles away. We were at 1,220 feet, so the descent to Waimanu’s jaw-dropping beach was almost straight down. When we reached it, no one else was there.

We pitched our tents just before dusk. I had a choice: orient mine to face our private black-sand beach or in the opposite direction, which opened onto a river with five waterfalls behind it. (After a rain, there can be more.) I’m an ocean man, but the waterfall view seemed the singular sight.

The cone of a ginger plant in the Waimanu Valley Photo: Jason Cohn

We washed in the river before dinner, with the comfort of knowing that no matter how hard we had climbed we would slip into our sleeping bags clean.

The following day, we hiked a mostly flat and well-marked but densely wooded 1.5-mile trail to the closest waterfall, filtering water for the rest of our trip from a stream along the way. Like Waipio, the Waimanu Valley was a former settlement, and as we walked we snacked on guavas, mangos and mountain apples, as had those early inhabitants. A few mosquitoes snacked on us, too.

In a single day in the Waimanu Valley, we traipsed through impossibly lush fields, feeling suddenly as though we were the only people on the planet; we swam beneath the thousand-foot Waiilikahi waterfall (if only we could have seen all the way to its top!), bathed in a placid river as though it were our own deep-soaking tub and body surfed in an ocean that flopped us around like scraps of kelp. Through all of it, we didn’t see another soul.

Well, not exactly. On the second day, a mongoose absconded with our breakfast bars and jerky (we heard it hissing and later found the wrappers). But we still had enough to eat. And when we headed back uphill—and into that other Hawaii of resorts and massages—we knew there would be less to carry.

Going to Hawaii? Take A Hike!

The most epic views of the islands are earned. Here’s where to find them.

Maui | The downhill Kaupo Gap Trail starts at 6,380 feet in the cloud forest of Haleakala National Park and ends 8.2 miles later with views of the Big Island across the Alenuihaha Channel. For a real challenge, start at the other end and hike up (nps.gov/hale/planyourvisit/hiking.htm).

Kauai | The graded, 11-mile Kalalau Trail, from Kee Beach to Kalalau Beach, hugs Kauai’s northwestern Na Pali Coast, with side trails leading into the Hanakapaiai and Kalalau Valleys. Expect to see a few wild goats along with mountain and ocean views throughout. Camp midway at Hanakoa or at Kalalau. Mile-long Kalalau Beach is one of Hawaii’s finest (kalalautrail.com).

Molokai | The Kalaupapa Trail starts at Palaau State Park, one of Hawaii’s largest expanses of old-growth tropical forest. From there, it spans 2.9 miles while descending 1,600 feet along 26 switchbacks to Kalaupapa National Historic Park (molokai-outdoors.com).

Oahu | The Poamoho Ridge Trail, in Oahu’s native Ewa Forest Reserve, offers views of the Kahana and Punaluu Valleys and the island’s eastern shore from atop the Koolau Range. On lease to the U.S. Army for military training, the area opens to recreational hikers only on weekends and holidays. A permit is required to access the 6-mile dirt road to the 3.5-mile trail, where vegetation turns to koa and ohia trees and vast carpets of uluhe ferns (permits at dlnr.hawaii.gov).

The Lowdown // Backpacking to the Waimanu Valley

Getting There: Many carriers fly from the western continental U.S. to Kona and Hilo International Airports, both on Hawaii’s Big Island. From Kona and Hilo, the drive to the Waipio Lookout is about 80 minutes. Leave your car at Waipio Valley Artworks, 15 minutes away by foot, for $20 a day (waipiovalleyartworks.com).

Jason Lee

Staying There: The Four Seasons Resort Hualalai is a luxurious antidote to nights in the wild (from about $795 a night, fourseasons.com). Register for a Waimanu campsite at camping.ehawaii.gov; $18 a night for nonresidents.

Hiking There: Download a Muliwai Trail and campground map at camping.ehawaii.gov. The hike is 19 miles round-trip from the Waipio Lookout, or 15.3 miles from the Muliwai trailhead, at the north end of Waipio Beach (to shave off a few miles, you can try to hitch a ride to the valley floor). To reach the Muliwai Trail and the Waimanu campground, you will need to ford two streams, so packable water shoes are recommended, as are trekking poles. Filter all water before drinking. In addition to any food you bring or fruit you find, you can catch a meal by fishing off the beach or catching freshwater prawns in Waimanu’s river. For guided hikes or equipment purchase on the Big Island, contact Hawaii Forest & Trail (hawaii-forest.com).