The high-speed, inflatable rafts you find on Maui are nothing like the raft that Huck Finn used to drift down the Mississippi. While passengers grip straps, these rafts fly, skimming and bouncing across the sea. Because they're so maneuverable, they go where the big boats can't—secret coves, sea caves, and remote beaches. Two-hour trips run around $50, half-day trips upward of $100. Although safe, these trips are not for the faint of heart. If you have back or neck problems or are pregnant, you should reconsider this activity.
Blue Water Rafting. One of the few ways to get to the stunning Kanaio Coast (the roadless southern coastline beyond Ahihi-Kinau), this rafting tour begins conveniently at the Kihei boat ramp on the South Shore. Dolphins, turtles, and other marine life are the highlight of this adventure, along with majestic sea caves, lava arches, and views of Haleakala. The Molokini stop is usually timed between the bigger catamarans, so you can enjoy the crater without the usual massive crowd. If conditions permit, you'll be able to snorkel the back wall, which has much more marine life than the inside. Kihei Boat Ramp, S. Kihei Rd., Kihei, HI, 96753. 808/879–7238. www.bluewaterrafting.com. From $55.
Ocean Riders. Start the day with a spectacular view of the sun rising above the West Maui Mountains, then cross the Au Au Channel to Lanai's Shipwreck Beach. After a short swim at a secluded beach, this tour circles Lanai, allowing you to view the island's 70 miles of remote coast. The "back side" of Lanai is one of Hawaii's unsung marvels, and you can expect to stop at three protected coves for snorkeling. You might chance upon sea turtles, monk seals, and a friendly reef shark, as well as rare varieties of angelfish and butterflyfish. Guides are knowledgeable and slow down long enough for you to marvel at sacred burial caves and interesting rock formations. Sit toward the back bench if you are sensitive to motion sickness. Tours include snorkel gear, a fruit breakfast, and a satisfying deli lunch. Mala Wharf, Front St., Lahaina, HI, 96761. 808/661–3586. www.mauioceanriders.com. From $139.
Redline Rafting. This company offers thrilling rides along south Maui's stunning Kanaio coast, revealing volcanic formations of sea caves, grottoes, and lava arches. There's a quick stop at La Perouse Bay, and then it's off to Molokini Crater for some snorkeling. The last stop in Makena gives you time to do more underwater exploring, spot sea turtles, and enjoy a deli lunch. Its rafts provide great seating comfort and shade. Whale-watching excursions are $50, and snorkel trips are $140. 2800 S. Kihei Rd., Kihei, HI, 96753. 808/757–9211. www.redlinerafting.com.