Road to Hana: You've probably heard of the Road to Hana, a narrow twisting road with nearly 50 one-lane bridges, carved into the lush rainforest and punctuated by breathtaking waterfalls, lava cliffs and sandy beaches. Before you start your drive in the town of Paia on the Hana Highway, arm yourself with the Hana CD guide. You can order the CD and map online in advance or buy it at one of many locations in Maui. Play the CD as you drive, and your private tour guide will tell you what's located where. Be on the lookout for the waterfall at Pua'a Ka'a State Wayside Park; the black-sand beach and lava tube at Wai'anapanapa State Park; the Halfway to Hana snack shop that sells mouth-watering, freshly baked banana bread; Kaihalulu Red-Sand Beach in Hana proper; and Ohe'o Gulch Pools, 10 miles past town.
Haleakala National Park: Haleakala Crater's lunar-like landscape is the piece de resistance of Haleakala National Park in Maui's upcountry. It's a two-hour drive from sea level to the summit at 10,023 feet, and it's amazing how many ecosystems you'll pass along the way. At 9,000 feet, you'll see the endangered silversword plant before you stop in to the visitor center at 9,740 feet (open sunrise to 3 p.m.) for exhibits about the native flora and fauna of the volcano. A trailhead there leads to an easy walk to an overlook. (More difficult hikes may be tackled at Haleakala, as well, from the trailhead there and another down at 7,990 feet.) Most people visit Puu Ulaula Overlook, the volcano's summit, to watch the sunrise. Check weather conditions before you head out. The summit can experience heavy winds, rain and even snow. In fact, it's generally 30 degrees cooler at the summit than in Kahului, so be sure to bring a jacket or blanket, warm hat and gloves. A glass-enclosed outlook offers panoramic views of the valley below, the Big Island, Kahoolawe, Lanai, Molokai and -- sometimes on very clear days -- Oahu.
Water Sports: Maui is a snorkel haven with no shortage of excellent locations for all ability levels. Try Black Rock at Kaanapali Beach; it's not uncommon to run into sea turtles there, and fish huddle along the lava/coral wall below Black Rock itself. Three miles offshore, Molokini Crater is a Marine Life Conservation District that boasts clear water with visibility of more than 100 feet. You might see monk seals, thousands of tropical fish, manta rays and whale sharks. If you'd like to try your hand at surfing or stand-up paddleboarding, you can book a lesson in Maui's waves.
Whale-watching: Although humpback whales call Alaska home during the summer, they spend November to mid-May in Maui. These majestic creatures hang around close to the shore, so you can whale watch from land, on water or by air. These grayish-black cetaceans often have white markings that help whale-watchers discern them from a distance. If you're visiting in season, don't miss a whale-watching excursion with your cruise line or through an independent operator. Many of these providers also offer snorkel or sunset boat trips.
Luaus: Any self-respecting visitor to Maui will attend at least one luau. With their Polynesian dancers in beautiful costumes, beachfront locations, authentic island cuisine and open bars, luaus are the cultural touchstone of the Hawaiian Islands -- and they're a lot of fun! Old Lahaina Luau is one of the best, set at the ocean's edge and wonderful for families. Choose either authentic mat seating on the floor or a seat at a table -- be sure to note your preference when making your reservation. (1251 Front Street, Lahaina; 800-248-5828; shows start at 5:15 p.m. in winter and 5:45 p.m. in summer). Couples and older families should consider the more upscale The Feast at Lele. It's a served dinner, rather than a buffet, with a mix of performances and dishes from a variety of Polynesian cultures. (505 Front Street, Lahaina; 866-244-5353).
Maui Ocean Center: You can still get up close and personal with Hawaii's marine life, even if you don't want to snorkel or scuba. The Maui Ocean Center is an aquarium with indoor and outdoor exhibits, including a turtle lagoon, shark pool, hands-on tide pool and a 54-foot-long clear acrylic tunnel you can walk through to see eye to eye with stingrays, sharks and close to 2,000 fish. The center also offers an ocean-friendly restaurant serving burgers, sandwiches and salads, and an excellent gift shop selling a variety of local products and crafts, as well as sealife-themed souvenirs. (192 Ma'alaea Road, Wailuku; 808-270-7000; open 9 a.m. to 5 p.m. daily, with last admission at 4:30 p.m.)
Golf: Maui is home to world-class golf courses, many overlooking the ocean. The natural beauty that surrounds you might even inspire a better golf game. You can book a round via your cruise ship's shore-excursion desk or consider these options: Kapalua Resort (877-527-2582) or Wailea Golf Club (888-328-MAUI).
Iao Valley State Park: This heritage site is home to the 1,200-foot Iao Needle, a rock outcropping covered in greenery set in the lush green Iao Valley. Paved trails take you to the viewpoint. After you've snapped your photos, you can learn from interactive exhibits in the visitor center or take a walk in the rainforest. (Located at the end of Iao Valley Road/Highway 32 in central Maui; open 7 a.m. to 7 p.m. daily).
Helicopter Tour: For a bird's-eye view of the island, book a helicopter tour that will fly you over the Haleakala Crater, the town of Hana and the nearby rainforest, Ohe'o Gulch, and the rugged northeast shoreline. Viewing these famous landmarks by air is invigorating.
Hiking and Eco-Tours: Try a hike or eco-tour for an up-close-and-personal exploration of Maui's rainforests or Haleakala Crater. There are many easy hikes on the island that culminate with a waterfall viewing; wear your swimsuit and cool off in the crystalline water at the waterfall's base. Other hikes can be more vigorous and even include a sea kayak component. For guided adventures, consider Hike Maui (808-879-5270 or 866-324-6284). Piiholo Ranch (808-270-8750) offers zip-line tours for a bit more adrenaline.
Horseback Riding: While most visitors journey up Haleakala in cars, perhaps daring to bike back down, a more unusual way to explore the volcano is on horseback. Options include descending Sliding Sands Trail to the crater floor or an easier excursion crossing at Haleakala Ranch.