At a bend in the Macal River, in the Mayan Mountains of Belize, Black Rock Lodge is an off-the-grid rainforest resort with 13 cabins. A restaurant on site serves organic fruits grown on the property, and all water is supplied by a nearby mountain spring. For adventure, head out early with a local guide for a jungle trek to a waterfall or a cave. Come afternoon, chill in your hammock—each cabin comes with one—for a siesta on the hill above the rushing river.

In Montana's Madison River valley—a 40-minute drive from Yellowstone National Par—the Lodge at Sun Ranch boasts a 26,000-acre property that's shared by a maximum of 16 guests. Scheduled to open in May, the ranch includes a 10,000-square-foot lodge with six rooms and two free-standing private cabins. Outside, Big Sky Country awaits with fly fishing, horseback riding, canoe trips and naturalist-led hikes.

Safari outfitter Conservation Corporation Africa operates this semi-permanent camp in Botswana's Chobe National Park, a preserve that is among the largest on the African continent. Zebras, wildebeests, cheetahs, leopards and lions are common sights. The light-on-the-land canvas tents have double beds and flush toilets. Hot-water bucket showers let you steam off at night with nothing above but the African stars.

This new Pacific coast resort couples deluxe accommodations with "the highest level of certified sustainability." Among its many eco efforts, the resort uses solar power to heat water; recycles its waste water for use in irrigation; and employs recycled-plastic roof tiles made from discarded bags used in the banana industry. Its paradise credentials include tide pools, rainforest, and a two-kilometer-long beach that connects to Manuel Antonio National Park.

In the center of the Indian subcontinent, on the edge of Pench National Park, Baghvan resort's 12 standalone bungalows are surrounded by teak trees and meandering jungle streams. Ayurvedic massage, yoga and wildlife safaris occupy your day. At night, sleep out under mosquito netting on your bungalow's rooftop terrace, jungle sounds all around, a twinkling Indian sky above.