By Ty Sawyer

Hawaii emerges straight from the world's collective imagination of paradise. With whales, dolphins and sharks, vast clouds of colorful butterflyfish, green sea turtles and whole crowds of creatures found only in the waters of this Polynesian undersea Mecca, Hawaii offers a vast realm of discovery and exploration. These spectacular volcanic wonderlands have all the blue thrills you can handle.

MAUI
From the "House of the Sun," Mount Haleakala, through the remarkable beauty of the Hana Road, and offshore to the one-of-a-kind diving off Molokini Crater, Maui features a complete set of the elements that define paradise. Still relatively unfettered by mass tourism, Maui revels in its pastoral charms -- but it's not without its share of top eateries and luxury resorts. Maui is also considered to have the greatest variety of diving in the Hawaiian Islands. Abundant sea turtles and sharks, and huge numbers of fish, define the underwater landscape here. Humpback whales crowd the sea during their birthing season, often causing roadblocks with their near-shore leaps.

The nearby uninhabited island of Kahoolawe is riddled with volcanic caverns. Diving the island of Molokai is like descending into a Wild West shootout   thrilling, unpredictable, seat-of-your-pants kind of diving. During most dives, lemon butterflyfish accompany divers like bright yellow leaves in an autumn wind. And the night diving here is modestly described as spectacular. Spanish dancer nudibranchs often take off like magic carpets during night dives, while eels, cowries, slipper and bull's-eye lobsters and a host of other nocturnal denizens will keep your dive light humming.

Slide show   A Mermaid’s Playground The beauty and mystery of the tropical undersea world. more photos

Almost a second home for Maui divers is the nearby island of Lanai, which seems to exist solely for the pleasure of divers. Here you'll find the world-famous lava domes of First and Second Cathedral, where shafts of light pierce the caverns like a thousand radiant swords. Beyond that is an incredible diversity of dive sites, in which a great variety of marine creatures play out their lives around this diver's playground.

The site called Pyramids gets its name from the sheer number of pyramid butterflyfish that flit around the top of the pinnacle. At another site, Fish Rock, menpachi, pipefish, viper moray, large cowries and whitetips headline a Hawaiian who's who list that will have you poring over ID books for hours after a day of diving  and that's just on the reef. Look to the blue and you'll have a good chance of seeing spotted eagle rays, manta rays and passing sharks, and in season, perhaps even humpback whales.

TOP DIVE SITES: MAUI

• Inside Crater
• Pyramids
• Enenue
• Back Wall
• Puu Koae
• Molokai
• Hidden Pinnacle
• Black Rock
• First Cathedral
• Second Cathedral
• Fish Rock

KAUAI
Known as the Garden Isle, Kauai should change its name to Hollywood's Preferred Backlot. It seems every inch of this lush island has appeared in a TV show or movie. Perhaps its two most famous natural features are the indescribable and awe-inspiring Na Pali Coast and the spectacular Waimea Canyon. In between are about a zillion waterfalls, and the wettest spot on earth, Mount Waialeale. With some of the most spectacular scenery on the planet, it's a mecca for hikers, mountain bikers, producers, adventurous types and, of course, divers.

Ty Sawyer / Sport Diver Magazine

The holy grail of diving in Hawaii, about a 45-minute boat ride away, comes with the menacing moniker of the "Forbidden Island," Ni'ihau. At sites like Ni'ihau Arches and Lehua Rock, divers frequently encounter endangered monk seals, eagle rays and blacktip sharks, as well as a busy metropolis of marine life, from huge schools of pennant, pyramid and milletseed butterflyfish to hawkfish, octopus and even rare morwongs.

Off Kauai, most of the diving is centered around Poipu Beach. Here you're (almost) guaranteed to encounter green sea turtles, often by the dozen. Sheraton Caverns lays claim to being the unofficial local hangout for these fascinating marine mammals. But they're not the only attraction. You'll also find loads of bluestripe snapper, whitetips and, for the observant, stunning nudibranchs, cowries, leaf fish, turkeyfish, triton trumpet shells and 7-11 crabs.

TOP DIVE SITES: KAUAI

• Sheraton Caverns
• Ice House
• General Store
• Fast Lanes
• Kaloa Landing
• Anaholo Bay
• Ni'ihau Arches (Ni'ihau)
• Lehua Rock (Ni'ihau)
• Pyramid Point (Ni'ihau)
• Vertical Awareness (Ni'ihau)

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