Hiking in Hawaiʻi

Kauaʻi has some of the best hiking in Hawaiʻi — the Kalalau Trail along the Nā Pali Coast being the ultimate. Across Waimea Canyon and Kōkeʻe State Park on the west side there are at least 25 trails, from an easy five-minute nature walk to punishing 1,300-foot descents you then have to climb back out of. On the east side, you can hike the Wailua River to Uluwehi Falls (reachable only by kayak), or climb about 760 feet up the Nounou East Trail — the Sleeping Giant, named for a ridgeline that looks like a face resting with its nose in the air. The Kalalau Trail on the north shore is one of the hardest hikes on the island: beyond the physical preparation, you need reservations booked well in advance, and daily permits are capped and fill fast.

Oʻahu has the most accessible hikes — easy to reach and to complete. Lēʻahi (Diamond Head) is the one most first-timers do: closest to Waikīkī, the island's most iconic landmark, with a required reservation plus parking and entrance fees. Mānoa Falls and the Koko Crater Stairs come next — parking is $7 at Mānoa and free at Koko — and all three draw crowds. Koko is the toughest of the three, 1,208 feet straight up with no switchbacks. For something more challenging, try a ridgeline like the Wiliwilinui Ridge Trail in ʻĀina Haina or the Kuliʻouʻou Ridge Trail in Hawaiʻi Kai. And beware the truly dangerous ones — the Olomana Trail (Three Peaks) includes rock climbing, ropes and precarious cliffside paths.

Maui offers a diverse range of terrain — dry coast, damp rainforest, cloud-kissed crater. The most popular hikes climb sacred Haleakalā, from short beginner walks to long treks that use pack mules. Keoneheʻeheʻe (Sliding Sands) descends into the crater, and the Pipiwai Trail weaves through a bamboo forest to Waimoku Falls. Because Haleakalā tops out at 10,023 feet, watch for altitude sickness near the summit, and if you're going for sunrise you'll need a reservation ahead of time. The Waiheʻe Ridge Trail climbs 2,500 feet and is well worth it, and there are shorter, easier options on the northwest side near the hotels, like the ʻŌhai Trail past the Nakalele Blowhole and the Kapalua Coastal Trail.

Geologically, Hawaiʻi Island is a fascinating place to hike. On the Hilo side, Hawaiʻi Volcanoes National Park is the most popular, with crater trails that feel like traversing the moon — and Puʻu o Lokuana, a former cinder quarry of blood-red dirt, feels more like Mars. The chance of seeing a live eruption makes hiking here unlike anywhere else in Hawaiʻi. Outside the park, you can do short waterfall walks like ʻAkaka Falls or intense altitude hikes up Mauna Kea. On the west side, the Pololū Valley Trail on the Kohala coast drops onto a black sand beach, and for history buffs the Kaʻaʻwaloa (Captain Cook Monument) Trail descends to Kealakekua Bay.

The trails in Hawaiʻi are some of the most beautiful in the country — and some of the most dangerous. Every year there's a disproportionate number of search-and-rescue operations, usually for visitors who didn't heed local cautions or underestimated the skill a trail demands. Experienced hikers from elsewhere are often the most vulnerable, because they're overconfident: an Appalachian ridgeline in New Hampshire is nothing like a rainforest ridgeline in Hawaiʻi.

The most underestimated hazard is flash flooding. Valley and waterfall trails — Pīpīwai on Maui, Mānoa Falls on Oʻahu, Kalihiwai on Kauaʻi — can go from dry to deadly within minutes of an afternoon thunderstorm. Even if the sky above you is clear, it may be pouring high in the mountains. If you're unsure about the weather, don't enter a valley trail; if you're already in one and the water starts to rise or change color, move to high ground immediately.

Do not wade or swim in freshwater with any open wound. Leptospirosis is a bacterial infection you can pick up from streams and waterfall pools if you have cuts or open wounds, and people are infected in Hawaiʻi every year. Sometimes the most inviting pools carry the highest risk.

The sun is more intense here than most visitors expect, even in winter. On exposed trails the UV is strong the moment the sun is up — start before 7 a.m. if you can, and always wear reef-safe sunscreen, which is required by state law (oxybenzone and octinoxate are banned; look for mineral-based zinc oxide).

Cliff trails without railings are deadly. The Kalalau and Olomana (Three Peaks) trails show how serious the exposure can be — one slippery step can be fatal, and people die on these trails every year underestimating the terrain.

Cell service is unreliable on most trails outside Honolulu. Download offline maps before you leave the trailhead — AllTrails works offline if you save the route in advance — and don't assume anyone can reach you if something goes wrong. On many hikes it could be hours, even overnight, before someone finds you.

Several of Hawaiʻi's most popular hikes require reservations, and the busiest trails often have the least availability. You can't show up hoping to book onsite — at most you'll be turned away at the gate. Plan ahead.

• Lēʻahi (Diamond Head), Oʻahu: non-residents book at gostateparks.hawaii.gov/diamondhead — $5 per person plus parking, no same-day walk-ups. Check early morning for cancellations.
• Haleakalā Sunrise, Maui: a tough one — slots release on recreation.gov exactly 60 days ahead at 7 a.m. HST and sell out in minutes, with a smaller batch 48 hours before. $1 per vehicle plus park entry. Miss both windows? Come for sunset instead — no reservation needed during standard hours.
• Kalalau Trail, Kauaʻi: the first two miles to Hanakāpīʻai Beach need a Hāʻena State Park day-use reservation (gohaena.com); beyond mile two, a separate Nā Pali Coast Wilderness Park camping permit, released 90 days ahead — one of the hardest permits in the state. Most visitors find the first two miles round-trip entirely sufficient.
• Mauna Kea, Hawaiʻi Island: no permit, but the summit road above the Visitor Information Station (9,200 ft) requires 4WD, and most rental contracts prohibit it. Stop at the VIS at least 30 minutes to acclimatize; altitude sickness at 13,796 feet is unpredictable and unrelated to fitness. Going with an experienced guide is the best option.
• Mānoa Falls, Oʻahu: no permit, but you pay for parking (and can't use the Lyon Arboretum lot).
• Kōkeʻe State Park, Kauaʻi: non-residents need an entry reservation through the state parks system, plus parking and lookout fees.

Gear

The single most important piece of gear is shoes with grip. Most trails here are slick when wet, which on windward and forested trails is most of the time — mud, exposed roots and steep grades make the wrong shoes frightening. Trail runners with aggressive soles handle nearly everything; full boots are overkill for most day hikes and you'll regret them in the humidity. Wear reef-safe sunscreen (legally required) on every trail, plus a hat and a sun shirt. Bring more water than you think — two liters minimum for anything over two hours, more in summer; coastal humidity is deceptive. Pack bug spray for waterfall and forest trails (Mānoa, Pīpīwai and most windward valleys have mosquitoes year-round), cash for parking and trailhead fees, and a headlamp for sunrise hikes like Haleakalā or early starts on Koko Crater.

When to Go

April–May and September–October are the best months to hike, statewide — drier mornings, cooler temperatures, lower flash-flood risk and fewer people. Winter (December–February) brings heavier rain, especially on windward sides, and some trails close temporarily after significant rainfall, so check Hawaiʻi State Parks alerts the morning of any hike. Summer is dry but hot — on any exposed trail, start before 6 a.m. and be off the ridge before 10. Never hike during or right after heavy rain; flash floods are a real risk.

Many of Hawaiʻi's most popular trails pass through or beside places of deep cultural significance — heiau (temples), burial sites, sacred summits and land stewarded by Native Hawaiians for centuries. Walking these trails is a privilege, not a right.

• Do not stack, move or remove rocks. It disturbs fragile native-plant ecology and trivializes a practice that marks sacred sites and navigation points. If you see stacked rocks, leave them alone.
• Stay on marked trails. Off-trail hiking damages ecosystems found nowhere else on earth and can put you on private or sacred land without realizing it.
• Mauna Kea is a sacred summit. The highest point in the archipelago and a place of genuine spiritual significance. If you visit, do so with reverence — leave nothing, take nothing, including rocks.
• The Haʻikū Stairs (Stairway to Heaven) is closed and being removed — don't attempt it. You'll risk a trespassing citation and your life.
• Leave the trail as you found it. Pack out whatever you pack in. Hawaiʻi's ecosystems are among the most fragile on earth.