As the largest of all the Hawaiian Islands, Hawaii's adventuring potential is enormous, given its motley terrain: Kilauea has been actively erupting for at least 300,000 years; the summits of Mauna Loa and Mauna Kea usually see snow in winter; and enormous fields of black lava rock are a dramatic contrast to the verdant rain forests and deep blue ocean.

Here's your guide to Big Island adventure, uniquely organized by terrain, from forest to Nirvana. As with most things in life, all you have to do is choose where you want to be. Prepare for full-on amazement. Then. Just. Go.

SKY

Kilauea's molten inferno is a likely stop in a typical Hawai'i Island itinerary. If you're staying on the Kona side (where all the luxe hotels are), the long drive to witness Tutu Pele's fiery show in Volcanoes National Park(even more glowy and churning these days in honor of the the NPS centennial—just kidding) can be a bit of a drag. That said, you can avoid the arduous traverse with a nighttime viewing in a chopper, Magnum P.I. style. Taking off from the Kona airport, Paradise Helicopters offers a two-hour tour of the island's volcanoes (you'll see Kilauea's flowing magma rivers and vaporous vents as well as Mauna Kea's world-class astronomical observatories and sometimes even snow!), lush valleys with black-sand beaches, and hidden waterfalls.

FOREST

Hawaii Forest & Trail, an exceptional adventure company whose trips include birding in Hakalau Forest National Wildlife Refuge and an 8–mile Kilauea lava hike, offers an exhilarating three-hour zipline adventure through a thick tree canopy near the funky northern town of Hawi. Once you're in the air, your feet don't touch the ground until you've completed nine tree-to-tree lines (the longest is more than a quarter-mile long) and gingerly ambled over five suspension bridges. If acrophobia is an issue, proceed at your own peril, but know that you're probably safer flying through the air on the course's twin galvanized-steel cables and double zip trollies than you would be jaywalking in Hawi. Expect numerous spikes in adrenaline, involuntary shrieking, and the flesh on your face to ripple back—all classic signs of thrilling exploits.

OCEAN

No trip to Hawaii is complete without a good snorkeling expedition. The Mauna Lani Sea Adventures catamaran offers a morning and afternoon snorkel sail to a 30-foot deep reef called Secrets where dolphins frolic and sea turtles stop by to get, ahem, "serviced" at what the boat captain calls a "turtle cleaning station." Here, turtles actually line up, sometimes 10 deep, to have shoals of fish eat algae off their shells. Symbiosis in action.

A nighttime manta ray snorkel with aptly monikered husband-and-wife guides James and Martina Wing of Manta Ray Advocates Hawaii is an experience of such once-in-a-lifetime proportions that it stays with you long after you're forced by your friends to stop talking about it. The 35-minute snorkel takes place at the Mauna Kea Beach Hotel, where a bright flood light shines into a small cove, attracting an all-you-can-eat buffet of plankton for the manta rays—toothless, barb-less, stinger-less filter feeders. After rigging you up with snorkel gear, James gives a five-minute iPad presentation on the graceful, gentle giants (with wing spans that can reach 13 feet!) and their efforts to keep them off the endangered list. At the manta feeding ground, an easy two-minute swim from the beach, you'll effortlessly float on the water's surface, keeping your hands and feet to yourself while up to 10 of these pelagic creatures glide around you. Through your snorkel, you'll say lots of muffled oh-my-gods and you'll even pinch yourself, convinced that such a surreal seascape could only be an acid-induced hallucination.

NIRVANA

The spa at the Mauna Lani Bay Hotel, consistently top ranked by Condé Nast Traveler, capitalizes on its paradisal surroundings in the name of nature-induced relaxation. Treatments take place in private outdoor thatch-roof hales, where no walls or doors make it easier for the sounds of the nearby ocean to lull you into an easy trance. If you're lucky enough to receive a lomi lomi massage from spa veteran Carole, she'll say a heartfelt Hawaiian blessing before she starts sequences of long, continuous strokes—the thoughtful choreography is designed to deeply nurture the body and improve the flow of energy. Beyond emerging with limbs that seem to float, you'll also enjoy the added benefit of a quiet mind—an otherworldly experience in its own right.

STAY & EAT

At the Mauna Lani Bay Hotel, located on the Kohala Coast, the 4,000-square-foot oceanside bungalows (Kevin Costner stayed in one for four months while filming Waterworld up the road in Kawaihae) sleep 4 to 6 people and come with their own swimming pools, hot tubs, outdoor showers, and cheffy kitchens. No need to fire-up the stove, though. You can go down the road to Waikaloa's Island Gourmet, an ABC Store on steroids, to shop for in-room snacks—poké, butter mochi, fresh pineapple dusted in tangy li hing mui powder, Kona coffee-flavored Pretz, cartons of POG juice. The hotel's breakfast buffet at the Bay Terrace is well-curated with everything from grilled swordfish fish to airy, sugar-coated malasadas. (And every haole requirement in between—bagels, oatmeal, Froot Loops, etc.) The Canoe House offers a nice upscale dinner: We recommend an all-appetizer route with pork-hash dumplings, Kona abalone, and tempura lobster. When dessert rolls around, try the refreshing shave ice, a kitchen-sink treat that's reminiscent of Filipino halo-halo with sweet red-bean paste, lilikoi sorbet, and a pillbox hat-like mini flan, all placed atop a mound of coarsely crushed ice.

Copper Barat the Mauna Kea Beach Hotel recently re-opened with a swanky cocktail scene complete with addictive bar snacks (spicy macadamia nuts, furikake french fries, inventive sushi rolls—the Mauna Kea Roll's buttery ahi and kampachi are balanced by crisp-tart green apple), fun libations (a maple-bourbon cocktail comes with a garnish of—what else?—eggs & bacon; the signature Mauna Kea mule is mixed with housemade ginger beer), plenty of mood lighting, and serious ocean-air mojo. Come at dusk for full atmospheric effect.

Save Merriman's Hawaii in Waimea for the last meal of your trip, since it will be the best. Here, chef Peter Merriman, who has been pioneering Hawaii's farm-to-table cuisine for more than 30 years, makes seriously elegant food from the bounty of Hawaiian farms. Just so you don't have to agonize over what to order, go for the "shared dinner," where nearly the entire menu parades itself onto your table. Favorites include bulgogi-style Kauai shrimp (don't forget to decapitate the suckers and slurp the immensely flavorful brains and juices out of their heads), Peter's original Caesar salad (a super-leafy classic with fried green tomatoes as croutons), misoyaki broccolini, and ahi ginger poke, an elevated homage to the dish that not only welcomed Merriman to the islands in the early 1980s, but was also responsible for his subsequent head-over-heels tumble into Hawaii's unique melting-pot gastronomy.

GETTING THERE

Hawaiian Airlines offers flights to Kona (via Honolulu) from SFO daily.