The best way to experience the aina—the land—on Kauai is to step off the beach and hike into the remote interior. You'll find waterfalls so tall you'll strain your neck looking, pools of crystal-clear water for swimming, tropical forests teeming with plant life, and ocean vistas that will make you wish you could stay forever.

For your safety wear sturdy shoes—preferably water-resistant ones. All hiking trails on Kauai are free, so far. There's a development plan in the works that could turn the Waimea Canyon and Kokee state parks into admission-charging destinations. Whatever it may be, it will be worth it. Following extensive flooding in early 2018, areas of the Napali Coast, including the Kalalau Trail, are undergoing repairs. Please check before visiting to make sure places are open.

Best Spots

Hanalei-Okolehao Trail. Okolehao basically translates to "moonshine" in Hawaiian. This trail follows the Hihimanu Ridge, which was established in the days of Prohibition, when this backyard liquor was distilled from the roots of ti plants. The 2-mile hike climbs 1,200 feet and offers a 360-degree view of Hanalei Bay and Waioli Valley. Your ascent begins at the China Ditch off the Hanalei River. Follow the trail through a lightly forested grove and then climb up a steep embankment. From here the trail is well marked. Most of the climb is lined with hala, ti, wild orchid, and eucalyptus. You'll get your first of many ocean views at mile marker 1. Hanalei, Hawaii, 96714.

Ho'opi'i Falls. Tucked among the winding roads and grassy pastures of Kapahi, 3 miles inland from Kapaa town, is an easy hike to two waterfalls. A 10-minute walk will deliver you to the creek. Follow it around to see the first set of falls. The more impressive second falls are a mere 25 minutes away. The swimming hole alone is worth the journey. Just climb the rooted path next to the first falls and turn left on the trail above. Turn left on the very next trail to descend back into the canyon and follow the leafy path that zigzags along the creek—the falls and the swimming hole lie below. Kapaa, Hawaii, 96746.

Kalalau Trail. Of all the hikes on the island, Kalalau Trail is by far the most famous and in many regards the most strenuous. A moderate hiker can handle the 2-mile trek to Hanakapiai Beach, and for the seasoned outdoorsman, the additional 2 miles up to the falls is manageable. But be prepared to rock-hop along a creek and ford waters that can get waist high during the rain. Round-trip to Hanakapiai Falls is 8 miles. This steep and often muddy trail is best approached with a walking stick. If there has been any steady rain, wait for drier days for a more enjoyable trek. The narrow Kalalau Trail delivers one startling ocean view after another along a path that is alternately shady and sunny. Wear hiking shoes or sandals, and bring drinking water since the creeks on the trail are not potable. Plenty of food is always encouraged on a strenuous hike such as this one. If you plan to venture the full 11 miles into Kalalau, you need to acquire a camping permit, either online or at the State Building in Lihue, for $20 per person per night. You should secure a permit well in advance of your trip. Following extensive flooding in early 2018, call to make sure that the trail is open and accessible. Hawaii, 96714. www.kalalautrail.com. $20 per person per night.

Mahaulepu Heritage Trail. This trail offers the novice hiker an accessible way to appreciate the rugged southern coast of Kauai. A cross-country trail wends its way along the water, high above the ocean, through a lava field, and past a sacred heiau (stone structure). Walk all the way to Mahaulepu, 2 miles north, for a two-hour round-trip. Hawaii, 96756. www.hikemahaulepu.org.

Sleeping Giant Trail. An easily accessible trail practically in the heart of Kapaa, the moderately strenuous Sleeping Giant Trail—or simply Sleeping Giant—gains 1,000 feet over 2 miles. We prefer an early-morning—say, sunrise—hike, with sparkling blue-water vistas, up the east-side trailhead, but there are other back-side approaches. At the top you can see a grassy grove with a picnic table. It is a local favorite, with many East Siders meeting here to exercise. Haleilio Rd., off Rte. 56, Wailua (Kauai County), Hawaii, 96766.

Waimea Canyon and Kokee State Park. This park contains a 50-mile network of hiking trails of varying difficulty that take you through acres of native forests, across the highest-elevation swamp in the world, to the river at the base of the canyon, and onto pinnacles of land sticking their necks out over Napali Coast. All hikers should register at Kokee Natural History Museum, where you can find trail maps, current trail information, and specific directions.

The Kukui Trail descends 2½ miles and 2,200 feet into Waimea Canyon to the edge of the Waimea River—it's a steep climb. The Awaawapuhi Trail, with 1,600 feet of elevation gains and losses over 3¼ miles, feels more gentle than the Kukui Trail, but it offers its own huffing-and-puffing sections in its descent along a spiny ridge to a perch overlooking the ocean.

The 3½-mile Alakai Swamp Trail is accessed via the Pihea Trail or a four-wheel-drive road. There's one strenuous valley section, but otherwise it's a pretty level trail—once you access it. This trail is a bird-watcher's delight and includes a painterly view of Wainiha and Hanalei valleys at the trail's end. The trail traverses the purported highest-elevation swamp in the world via a boardwalk so as not to disturb the fragile plant and wildlife. It is typically the coolest of the hikes due to the tree canopy, elevation, and cloud coverage.

The Canyon Trail offers much in its short trek: spectacular vistas of the canyon and the only dependable waterfall in Waimea Canyon. The easy 2-mile hike can be cut in half if you have a four-wheel-drive vehicle. The late-afternoon sun sets the canyon walls ablaze in color. Kokee Natural History Museum, 3600 Kokee Rd., Kekaha, Hawaii, 96752. 808/335–9975; www.kokee.org.

Equipment and Tours

Kauai Nature Tours. Father-and-son scientists started this hiking tour business. As such, their emphasis is on education and the environment. If you're interested in flora, fauna, volcanology, geology, oceanography, and the like, this is the company for you. They offer daylong hikes along coastal areas, beaches, and in the mountains. If you have a desire to see a specific location, just ask. They will do custom hikes to spots they don't normally hit if there is interest. Hikes range from easy to strenuous. Transportation is often provided from your hotel. 5162 Lawai Rd., Koloa, Hawaii, 96756. 808/742–8305; 888/233–8365; www.kauainaturetours.com. From $155.

Princeville Ranch Adventures. This 4-mile hike traverses Princeville Ranch, crossing through a rain forest and to a five-tier waterfall for lunch and swimming. Moderately strenuous hiking is required. Rte. 56, between mile markers 27 and 28, Princeville, Hawaii, 96722. 808/826–7669; 888/955–7669; www.princevilleranch.com. $129.