Its proximity to the world’s second-largest barrier reef makes the 50-square-mile Honduran island of Roatan a magnet for a special breed of marine-life geek. Self-taught submarine builder Karl Stanley takes travelers on reef dives off Half Moon Bay in his homemade three-passenger craft, Idabel. Unless you’re James Cameron, there’s no other way to go this deep: Stanley Submarines expeditions (from $400; stanleysubmarines.com) range from 90 minutes to nine hours and descend to 2,000 feet—or about 1,940 feet farther than the average scuba trip. On the way down, you’ll glimpse bioluminescent coral and feather-dusterlike sea lilies, as well as deep-dwelling Dumbo octopuses and elusive six-gill sharks that have never seen the light of day (or humans). Back on shore, bypass the West Side’s touristy beach-bar scene—particularly when the cruise ships dock—in favor of the minimally developed East End. Primo lodging can be found at the upscale Las Verandas Hotel and Villas (from $245; las-verandas.com), which welcomed its first guests last month. Also worth a stop: the newly opened 160-acre Blue Harbor Tropical Arboretum (tours $13; Main Rd.; blueharbortropicalarboretum.com), where guides dole out samples of ripe guavas, sweet limes, and creamy soursop straight from the trees. At remote Camp Bay, professional kite surfer Marilou Lavallée hosts private lessons just off the two-mile-long white-sand strand ($75 per hour; e-mail firstname.lastname@example.org to book). Refuel after a day of riding at the tiny La Sirena de Camp Bay (504-9564-6866), a thatched-roof hut plunked on the end of a wooden pier, where intrepid epicures are rewarded with stiff rum punch, spicy lionfish ceviche, and just-caught lobster.
The thrill-o-meter: A rip-roaring, heart-on-the-floor rush—better buy travel insurance.