Swim with Sharks, Soar Above Volcanoes: Your Ultimate Big Island Adventure Guide

The first time you drop into the Pacific off the Kona coast after dark, a spotlight in one hand and 1,500 feet of black water below, you’re not sure what feels more surreal — the bioluminescent trail left by your fins or the 16-foot wingspan of a manta ray emerging from the void. That moment, somewhere between terror and wonder, is the one people come to the Big Island for. Not just to see Hawaii, but to feel it from the inside out.

This guide covers the island’s most extreme adventures — from swimming with sharks to standing at the edge of an active volcano — and it’s built for travelers who want both the adrenaline and the logistics that make it possible. Whether you’re a certified diver, a confident snorkeler, or someone who prefers to keep both feet on lava rock, each section gives you the real numbers, real timing, and real trade-offs so you can decide what fits your trip.

That scale means you can snorkel with mantas in the morning and hike a volcano in the afternoon, but only if you plan the distances. The island’s two airports — Ellison Onizuka Kona International Airport (KOA) on the leeward side and Hilo International Airport (ITO) on the windward side — bookend a landmass that takes 2–3 hours to cross by car. Renting a car is the standard recommendation, and most visitors stay an average of eight days, which gives you just enough time to hit the highlights without rushing.

Below you’ll find six core experiences, each with the practical details you need to book, pack, and prepare. The overview table gives you a quick read on which ones fit your travel style, and the deeper dives afterward cover the specifics.

Manta Ray Night Dive — Kona Coast

This is the experience that puts the Big Island on every diver’s short list. The Kona coast is shielded by Mauna Loa and Hualālai volcanoes, which block the trade winds and produce calm, clear water with visibility frequently exceeding 100 feet year-round. At night, operators lower lights from the boat to attract plankton, which in turn draws manta rays with wingspans up to 16 feet. The mantas feed directly above and around you, often close enough to touch — though the no-touch policy is strictly enforced for the animals’ safety.

Kona Honu Divers runs this dive with a conservation-first approach, and their guides have over 200 years of combined experience. The minimum certification is Open Water Diver, and you’ll need to bring your certification card and logbook. If you’re not certified, a “Discover Scuba Diving” experience with a local shop can get you in the water under direct supervision.

If your schedule only allows one night dive on the island, this is the one. The mantas are reliable year-round, and the combination of calm Kona water and the sheer size of the animals makes it accessible for newly certified divers who are comfortable in open water.

For a deeper look at this specific experience, check out our full guide to Big Island night diving with manta rays.

Black Water Night Dive — Offshore Kona

If the manta dive feels like a dream, the black water night dive feels like a science experiment. This advanced dive takes place miles offshore over thousands of feet of open ocean. You’re tethered to the boat and drift in the water column as lights attract deep-sea life that normally never rises above the mesopelagic zone: bioluminescent jellies, larval fish, squid, and glass-like crustaceans that you’d need a submersible to see anywhere else.

Kona Honu Divers runs this as a dedicated tour, and it requires advanced open water certification or significant experience. The dive is held in water where the bottom is unreachable — you’re suspended in open ocean, attached to the boat by a line, watching creatures that spend their days at depths of 1,000 feet or more. The experience is as much about surrender as it is about observation.

Book the black water dive through Kona Honu Divers’ black water night dive tour. Slots are limited — the operator keeps groups small to minimize light pollution and disturbance to the animals.

Shark Diving & Snorkeling — Kona Coast & South Point

Swimming with sharks in Hawaii is safe when done responsibly with experienced guides who follow no-touch, no-feed policies. The Big Island’s Kona Coast and South Point are popular locations for cageless shark encounters, where you observe Galapagos sharks, sandbar sharks, tiger sharks, white-tip reef sharks, and hammerheads in their natural deep-water habitat. Great white sharks are rare visitors to Hawaiian waters, mainly appearing offshore during winter months.

Shark diving is possible year-round, with spring (March–May) and fall (September–November) offering the best conditions for beginners and experienced divers alike. Sharks are typically found at depths around 150–200 feet, though seasonal depths vary by species. Non-divers can observe sharks from boats through shark snorkeling and viewing tours, or deep-water shark viewing excursions that keep participants at the surface.

Cageless shark diving is encouraged by many conservationists because it allows natural interactions without altering shark behavior. Cage diving, by contrast, may condition sharks to associate boats with food. Operators on the Big Island overwhelmingly run cageless experiences, and the focus is on observation rather than provocation.

If you want to book a dedicated shark encounter, Viator offers a shark diving tour on the Big Island that matches this activity.

Volcanoes National Park — Kīlauea & Mauna Loa

The Big Island is the only Hawaiian island with active volcanoes you can visit safely. Kīlauea is the most active volcano on Earth, and Mauna Loa — the world’s largest active volcano by volume — shares the island with it. A third underwater volcano, Loʻihi, is forming new land off the southeast coast and has risen more than 10,000 feet from the seafloor, though it won’t break the surface for tens of thousands of years.

Most of Volcanoes National Park sits in the Kaʻu district, and Hilo is the closest major town with an airport. The park’s status changes frequently — eruptions pause and resume, trails close and reopen. Before you go, check the USGS Kīlauea volcano updates for real-time conditions. The park is accessible year-round, but windward weather means rain is common — pack layers and waterproof gear.

If you’re short on time, prioritize the Kīlauea summit area and the Chain of Craters Road. The park also borders Punaluʻu Black Sand Beach in the Kaʻu region — a good add-on if you’re driving south. For hikers, the park offers trails that cross recent lava flows and pass through native forest, though some routes close without notice during active eruptions.

For more on hiking the island’s volcanic terrain, read our guide to volcano views and hiking Hawaii’s most thrilling trails.

Kona Reef & Lava Tube Exploration

The same volcanic forces that built the island also created its underwater topography. Ancient lava flows formed lava tubes, archways, caverns, and coral reefs growing directly over volcanic rock. Morning charters from Kona visit sites like Golden Arches and Turtle Pinnacle — named for the green sea turtles (honu) that use them as cleaning stations.

These dives are accessible to Open Water divers and offer the best mix of geology and marine life. The water is calm year-round, visibility often exceeds 100 feet, and currents are gentle. Operators like Kona Honu Divers run two-tank morning trips that hit two different sites in one outing, which is the most efficient way to see multiple reef systems without burning a full day.

A deeper option is Au Au Canyon, a site with sheer lava cliffs and rare deep-water species. It’s known locally as “Turtle Heaven” because of the number of green sea turtles that gather at cleaning stations along the canyon walls. This site suits more experienced divers due to its depth and occasional current.

Snorkeling & Surface Adventures

Not everyone on the trip dives — and the Big Island makes sure they don’t feel left out. The manta ray night snorkel, run by operators like Kona Snorkel Trips, uses the same light-and-plankton technique as the dive but keeps participants at the surface. Mantas feed right below you, often close enough that you can see their individual gill slits and the patterns on their bellies.

Daytime snorkeling at Kealakekua Bay — the site where Captain James Cook first set foot on Hawaiian soil in 1779 — offers clear water, vibrant coral schools, and deep historical significance. The bay is a marine sanctuary, so no fishing is allowed, and the fish populations are dense and unafraid of swimmers. Access is by kayak, boat tour, or a steep hike from the cliff above.

If you want to book a dedicated snorkeling excursion, Viator has a Big Island snorkeling tour that covers multiple reef sites.

Planning Your Big Island Adventure — Logistics, Seasons & Gear

The single biggest friction point on the Big Island is distance. The island is larger than all other Hawaiian islands combined, and driving from Kona to Hilo takes 2–3 hours each way. Most visitors stay an average of eight days, and the standard recommendation is to rent a car — public transit won’t get you to dive sites, trailheads, or the national park on a reasonable schedule. Discount Hawaii Rental Car is a commonly recommended provider.

If you don’t want to drive, guided tours like the Big Island Circle Tour offer hotel pickup and comprehensive sightseeing. But for the activities in this guide — especially the dives and shark encounters — having your own vehicle gives you the flexibility to adjust for weather and timing.

The best months to visit are May and October for fewer crowds, good weather, and lower costs. Winter brings more rain on the windward side (Hilo, Hamakua Coast, Puna), while leeward areas like Kona stay warm and sunny year-round. Some Kohala Coast beaches become dangerous in winter due to strong currents — check conditions before swimming.

Gear-wise, the research recommends bringing your own mask, dive computer, and reef-safe sunscreen if you plan to dive regularly. Renting BCDs, regulators, and wetsuits on site saves luggage space. A light jacket is useful for boat rides after dark. If you’re planning to capture underwater footage, a compact action camera like the DJI Osmo Action 6 Bundle handles low-light conditions well and mounts easily to a mask strap.

Measured from its seafloor base, Mauna Kea is the world’s tallest mountain — taller than Mount Everest. If you have a clear night, the summit offers some of the best stargazing on the planet. Check out our guide to Hawaiian stargazing on Mauna Kea for visitor center details and summit access rules.

Before You Go — Big Island Adventure

Do I need to be a certified diver for all of these activities?

No. The manta ray night dive and reef dives require Open Water certification, but the manta ray night snorkel and shark viewing tours don’t. If you’re not certified, a “Discover Scuba Diving” experience lets you try scuba under direct supervision without a full course.

What’s the best way to get around the Big Island?

Renting a car is strongly recommended. The island is larger than all other Hawaiian islands combined, and public transit won’t reach most dive operators, trailheads, or the national park. Guided circle tours are an alternative if you prefer not to drive.

When is the worst time to visit for adventure activities?

Winter (November–April) brings more rain to windward areas and larger surf to north-facing beaches. While Kona stays relatively sunny, some Kohala Coast beaches become dangerous for swimming, and windward snorkeling spots can have reduced visibility.

Can I see lava flowing right now?

It depends. Kīlauea is the most active volcano, but eruptions pause and resume. Check the USGS Kīlauea updates before your trip. Even without active lava flow, the summit caldera, steam vents, and recent flows are worth visiting.

Is shark diving safe for beginners?

Yes, when done with experienced guides who follow no-touch, no-feed policies. Spring and fall offer the best conditions for beginners. Cageless shark diving is the standard on the Big Island, and operators prioritize safety briefings and small groups.

One Island, Two Extremes

The Big Island doesn’t let you ease into it. You arrive, pick a direction, and within 48 hours you’re either 60 feet underwater watching a manta ray somersault through a cloud of plankton or standing on a volcanic caldera that was flowing lava the week before. That whiplash is the point — the island was built by fire and surrounded by life, and the best way to experience it is to let both extremes shape your itinerary.

For more on the island’s marine life, including seasonal whale encounters, read our guide to whale watching in Hawaii.

References

Deep Blue Eco Tours. “Swimming with Sharks in Hawaii.” Deep Blue Eco Tours Blog, 2024. ↗

The Hawaii Vacation Guide. “Hawaii Big Island Travel Guide.” The Hawaii Vacation Guide, 2024. ↗

Kona Snorkel Trips. “Big Island Hawaii Scuba: Why Kona is Hawaii’s Premier Diving Destination.” Kona Snorkel Trips Blog, 2024. ↗

If you’re building a full Big Island itinerary, pair this guide with our deep dives on off-road adventures on Lanai and canyoneering in Hawaii for more ways to push past the resort boundaries. The island rewards travelers who come with a plan — and a willingness to get wet, dusty, and completely awestruck.