Outdoor Activities in Big Island

Stargazing at Mauna Kea Visitor Information Station

The Visitor Information Station sits at about 9,200 feet, above much of the atmosphere's moisture and light pollution. Free public stargazing programs have historically run on clear evenings, with volunteer astronomers setting up telescopes pointed at Saturn's rings, the Orion Nebula, or whatever's prominent that season. The air feels thin and cold even in summer, often dipping into the mid-40s°F after dark. Bring layers, a headlamp with a red filter, and plan to arrive before sunset so your body can start adjusting to the altitude. Access rules for the upper mountain have been evolving under the Maunakea Stewardship and Oversight Authority, so check their current policies before driving up.

Difficulty

Easy (stargazing); Moderate (altitude adjustment)

Duration

2-3 hours at the station

Best season

Year-round, though November through February tends to offer the darkest and clearest skies

Lava Viewing at Hawaii Volcanoes National Park

Kilauea's activity comes in cycles, and whether you'll see flowing lava depends on the volcano's mood during your visit. Even during quiet periods, steam rises from vents along Crater Rim Drive and the smell of sulfur hangs over the caldera. When the summit or rift zone is active, the orange glow against the night sky is visible from overlooks off Chain of Craters Road. The park charges $30 per vehicle for a 7-day pass. Worth noting, the landscape changes between visits, with new flows and collapses reshaping the terrain month to month.

Difficulty

Easy (overlook viewing); Moderate (longer walks to active flow areas)

Duration

Half day to full day

Best season

Year-round; drier months (May through September) make trail access more reliable

Horseback Riding in Waipio Valley

The valley floor sits about 900 feet below the lookout, accessible only by one of the steepest paved roads in the state. Several outfitters run guided rides along the black-sand beach and through taro farms, where the river braids across flat ground and the air smells like wet vegetation. You'll hear the horse's hooves, the surf, and birdsong echoing off 2,000-foot cliffs. Most rides last about 2 hours and don't require prior experience. The valley is sacred in Hawaiian tradition, so follow your guide's direction on where to go.

Difficulty

Easy to moderate (guided rides)

Duration

2-2.5 hours

Best season

Summer months tend to be drier; the valley can flood after heavy rains on the Hamakua Coast

Cycling the Kohala Mountain Road

Highway 250 runs about 20 miles between Hawi and Waimea through open ranch country, climbing to around 3,500 feet at its highest point before dropping into the cool grasslands of Waimea. The road is paved, two lanes, and carries relatively light traffic outside commute hours. On clear mornings, views from the upper sections extend across Kohala pastures to the ocean. You'll feel the temperature shift as you gain altitude, from warm and breezy in Hawi to noticeably cooler near the road's summit. Bike rentals are available in Kailua-Kona, about 40 minutes south of Hawi.

Difficulty

Moderate to strenuous (sustained climbing)

Duration

3-5 hours for the full route

Best season

Year-round; mornings tend to be clearest before afternoon clouds build over the mountain

Zip-lining Over the Umauma River

The North Hilo stretch of the Hamakua Coast has a few zip-line operations set above river gorges and waterfalls. The Umauma area, about 16 miles north of Hilo, runs lines that cross above a series of cascading falls surrounded by dense tropical canopy. You'll hear the water rushing below and feel mist on the longer traverses. Most courses include 7 to 9 lines and take about 2 to 3 hours, with weight and age restrictions that vary by operator. The rainforest setting is thick, humid, and loud with birdsong.

Difficulty

Easy to moderate (guided, no hiking required)

Duration

2-3 hours

Best season

Year-round; drier months reduce the chance of weather delays

Exploring Kaumana Caves

This lava tube sits about 2 miles up Kaumana Drive from downtown Hilo. A staircase descends into the cave entrance, where the temperature drops noticeably and the air goes still. The tube extends in two directions, with the left branch generally more accessible. The floor is rough, uneven a'a lava, slippery in spots from moisture. Bring your own headlamp and wear closed-toe shoes with good grip. There are no guides on site and no fees. The cave formed during an 1881 Mauna Loa eruption that nearly reached Hilo.

Difficulty

Moderate (uneven footing, complete darkness)

Duration

30-60 minutes

Best season

Year-round; the cave sits underground, so surface weather has little effect

Kilauea Iki Trail

The trail begins at the Kilauea Iki Overlook parking area in Hawaii Volcanoes National Park and descends through a canopy of ohia lehua and tree ferns into the Kilauea Iki crater. You'll cross the crater floor, which filled with lava during a 1959 eruption that sent fountains nearly 1,900 feet into the air. The surface is hardened pahoehoe, still warm in spots, with steam seeping through cracks. The loop covers about 4 miles with roughly 400 feet of elevation change. On the crater floor, the air is noticeably warmer and the sulfur smell sharpens near active vents.

Difficulty

Moderate

Duration

2-3 hours

Best season

Year-round; May through September means less slippery footing on the forested descent

Pololu Valley Trail

The trail drops from the Pololu Valley Lookout at the northern tip of the Kohala Coast to a black-sand beach. The descent is steep, about half a mile one way with around 400 feet of elevation change. Footing is uneven, a mix of packed dirt and exposed roots. At the bottom, the beach is wild and usually empty, backed by ironwood trees. The surf tends to be too rough for swimming. Wind can be strong at the lookout. You'll find the trailhead about 9 miles past Hawi on Highway 270.

Difficulty

Moderate (steep descent and return climb)

Duration

45 minutes to 1.5 hours round trip, depending on time at the beach

Best season

Year-round; mornings before 10 AM tend to have clearest light and fewer people

Kaawaloa Trail to the Captain Cook Monument

This trail descends roughly 1,300 feet over about 1.75 miles from the trailhead off Napoopoo Road to the shore of Kealakekua Bay. A white obelisk marks the spot where Captain James Cook was killed in February 1779. The terrain is dry, exposed scrubland with kiawe trees offering minimal shade, and the sun radiates off the bare rock on the climb back. The descent takes about an hour, the return closer to 2. The reward at the bottom is the snorkeling, which is likely the best shore access on the island, with clear water and spinner dolphins that frequent the bay. Carry at least 2 liters of water per person.

Difficulty

Strenuous (steep, exposed, hot on return)

Duration

3-4 hours round trip including swim time

Best season

Year-round; morning starts are cooler and the bay is calmer before afternoon winds build

Mauna Kea Summit Trail (Humuula Trail)

The trail begins near the Visitor Information Station on Mauna Kea Access Road and climbs about 4,600 feet over roughly 6 miles to the summit, crossing cinder desert, alpine scrubland, and eventually barren volcanic rock above the cloud line. The round trip covers approximately 12 miles. Altitude is the real challenge. Headaches, nausea, and shortness of breath are common above 10,000 feet, and some hikers turn back well before the top. Temperatures near the summit can drop below freezing even in summer, and the thin atmosphere makes sunburn faster than you'd expect. Pack warm layers, high-SPF sunscreen, at least 3 liters of water, and calorie-dense snacks.

Difficulty

Very strenuous (altitude, distance, exposure)

Duration

7-10 hours

Best season

June through September for the best weather window; winter brings snow and ice above 11,000 feet

Puu Loa Petroglyphs Trail

A flat, easy walk across a pahoehoe lava field in Hawaii Volcanoes National Park leads to one of the largest petroglyph fields in all of Hawaii. The site contains thousands of carvings made over several centuries by Native Hawaiian travelers passing between the coast and uplands. A boardwalk protects the most concentrated area, but petroglyphs appear scattered across the surrounding rock as well. The trailhead sits along Chain of Craters Road, about 20 miles from the park entrance. The lava surface reflects heat, so morning visits are more comfortable. You can feel the warmth radiating through your shoe soles by midday.

Difficulty

Easy (flat, well-marked)

Duration

45 minutes to 1 hour round trip

Best season

Year-round; early mornings avoid the heat bouncing off the lava field

Snorkeling at Two Step (Honaunau Bay)

Two natural lava steps at the water's edge serve as the entry point for what might be the most accessible shore snorkeling on the island. The reef starts within a few feet of the entry, with coral formations, tropical fish, and the occasional hawksbill turtle gliding past. Visibility tends to run 50 to 80 feet on calm mornings. The bay sits next to Puuhonua o Honaunau National Historical Park on the South Kona coast. Parking fills up by mid-morning on weekends, so arriving before 8 AM gives you the best shot at a spot and the calmest water. Bring reef-safe sunscreen and your own gear.

Difficulty

Easy to moderate (rocky entry, no sandy beach)

Duration

1-2 hours

Best season

Year-round; calmest conditions from April through October

Kayaking and Snorkeling at Kealakekua Bay

Paddling from Napoopoo to the Captain Cook Monument on the far side of the bay covers about 1 mile of open water. The bay is a marine life conservation district, with dense coral cover and large schools of yellow tang along the monument's shore. Several Kona-based outfitters run guided tours that bundle the paddle and snorkel time. Conditions are generally glassy in the morning, but wind chop can build by early afternoon. Independent kayak access typically requires a permit reserved through the state in advance. The water clarity near the monument is consistently excellent, often 60-plus feet of visibility.

Difficulty

Easy to moderate (open water crossing)

Duration

3-4 hours for a guided trip

Best season

Year-round; morning departures before trade winds build

Manta Ray Night Snorkel off Keauhou Bay

Tour operators anchor boats off the Keauhou coast at dusk, lower underwater lights that attract plankton, and manta rays with wingspans reaching 10 to 12 feet glide in to feed directly below you. You float on the surface holding a lit board while the mantas loop and barrel-roll through the plankton cloud, sometimes passing within arm's reach. The water stays warm, around 78 to 80°F even after dark, but the whole experience has a strange, slightly eerie quality. Most tours last about 2 hours including transit and briefing. Sightings are not guaranteed, though historical success rates have been above 90%.

Difficulty

Easy (floating on the surface, life vest provided)

Duration

2 hours

Best season

Year-round; manta sightings are not strongly seasonal

Swimming at Hapuna Beach State Recreation Area

Hapuna Beach is a wide crescent of white sand along the Kohala Coast, about 30 miles north of Kailua-Kona. The beach stretches roughly half a mile and the water is typically clear turquoise over a sandy bottom. Summer months bring calm surf suited to swimming, while winter swells produce a strong shore break and dangerous currents that catch people off guard. Lifeguards are on duty. Facilities include restrooms, showers, and a shaded picnic area. A state parking fee applies for non-resident vehicles.

Difficulty

Easy (summer); Moderate to hazardous (winter shore break)

Duration

Open

Best season

May through September for swimming; winter for watching the surf from the sand

Deep-sea Fishing out of Honokohau Harbor

The Kona coast drops to depths exceeding 6,000 feet within a mile of the shoreline, which is why the area has a long-standing reputation as one of the world's premier blue marlin fisheries. Charter boats depart from Honokohau Harbor, between Kailua-Kona and the airport, for half-day or full-day trips targeting Pacific blue marlin, yellowfin tuna, mahimahi, and ono. The International Billfish Tournament has been running here since 1959. Expect to pay roughly $200 to $300 per person for a shared half-day trip, with private charters considerably more. The smell of diesel and bait at the harbor at 6 AM is part of the ritual.

Difficulty

Easy (charter crew handles rigging and boat)

Duration

Half day (4 hours) or full day (8 hours)

Best season

June through September tends to produce the largest marlin; smaller game fish bite year-round

This 24-acre Japanese garden sits on Banyan Drive in Hilo, overlooking Hilo Bay and Coconut Island. It was dedicated in 1917 and named for Queen Liliuokalani. Stone lanterns, arched bridges, pagodas, and koi ponds spread across manicured grounds shaded by mature banyan trees. The garden is quiet on weekday mornings, with the sound of gentle waves from the bay carrying through the grounds. It feels more like a neighborhood retreat than a tourist attraction.

Highlights: Stone bridges and pagodas, koi ponds, views of Coconut Island and Hilo Bay, mature banyan canopy

Located along scenic Onomea Bay about 7 miles north of Hilo, this 17-acre garden drops through a steep valley to the ocean. The collection includes over 2,000 species of tropical plants from around the world. A paved boardwalk winds through the canopy, past waterfalls, and along a stream bed. The air under the tree cover is thick and humid, and the smell of ginger and plumeria follows you along the lower trail. Admission runs around $25 for adults.

Highlights: Three waterfalls along the valley trail, Onomea Bay overlook, orchid collection, palm forest with over 200 species

A short 0.4-mile paved loop through dense tropical vegetation leads to views of two waterfalls. Akaka Falls drops 442 feet into a gorge choked with monstera and bamboo. Kahuna Falls, visible from a second overlook along the same loop, is smaller but still worth the stop. The park sits about 11 miles north of Hilo off the Hawaii Belt Road. The trail is accessible and takes around 20 to 30 minutes. A state park vehicle fee and per-person entry fee apply.

Highlights: 442-foot Akaka Falls, Kahuna Falls overlook, giant bamboo groves and tree ferns along the loop

A 43-acre park on the shore of Waiakea Pond in Hilo, connected to the bay by the Wailoa River. The park includes a war memorial, a tsunami memorial, and open lawns under large trees where locals fish and picnic. It feels like a neighborhood park, and that's part of the appeal. The pond holds tilapia and mullet, and you'll likely see people casting from the banks in the early morning light. Egrets stalk the shallows near the river mouth.

Highlights: King Kamehameha statue, Vietnam War memorial, Wailoa Center gallery, fishing from the pond banks