Five feet down in the liquid blue somewhere off leeward Lanai, I see a subtle flutter amid the busy commotion of butterfly fish on a cluster of pinkish brain coral. I swim down a few feet to the lava shelf and recognize the rippling body of a tiny brown-and-white-speckled snowflake eel. The little guy munches happily on coral. I smile with the knowledge that in all this sun-dappled marine splendor, ours is the only snorkel boat.

Hawaii shelters many snorkel havens like this nameless Lanai reef, reachable only by boat. Scores of commercial snorkel cruises troll these waters--many crowding the same areas--in search of underwater camera fodder. Most snorkel boats take you to the same-old, same-old. On Maui, the masses go to Molokini, an uninhabited volcanic crescent a half-hour off Maui--a fine snorkel spot with multitudes of tame fish and just as many people (yes, those are boats lined up). For solitude and a more scenic -- albeit bumpy -- ride, sign up with Maui Ocean Riders Adventure Rafting, the only snorkel cruise that I know of which circumnavigates the neighboring island of Lanai. Trips are limited to 18 people. The skippers know the back side of Lanai like the back of their hand. They'll take you to underwater ledges that sprout colonies of brain, cauliflower, and rice coral, where a frolicking piscine menagerie spans the entire color spectrum, with highlights like darting purple anthias and neon green parrot fish. Close encounters with leaping pods of whales (our boat witnessed a half-dozen males playfully chasing a female) are routine during the winter months. The sea critters will not be as numerous or as bodacious as you might find at Molokini. But the solitude and the supremely clear waters are oh so choice. For the weak of stomache, pack the dramamine; the channel crossing can be bumpy.

DETAILS: Maui Ocean Riders leaves from Mala Wharf in Lahaina. The Lanai circle trip departs at 7 Monday through Saturday and returns at 2:30; $129, $99 ages 5–12, breakfast and lunch included. CONTACT: (808) 661-3586.

Caveat Emptor: This info was good last time we checked. It might not be anymore by the time you read this.

—Alex, 07/29/06