Kauai’s lush tropical interior may have earned it the nickname the Garden Island, but the small Hawaiian island’s most scenic panoramas can be found on the remote northwestern shore, where miles of sheer cliffs tower thousands of feet above the aquamarine Pacific Ocean. The iconic Na Pali coast (translated literally, “the cliffs”) is pristine and undeveloped: no roads, no hotels, no mobile phone signal. The lure of such unspoiled terrain is catnip to intrepid vacationers and seasoned outdoorsmen alike.

While there are several ways to take in this rugged coast – by helicopter; sailboat; Zodiac speedboat; or the 11 mile-long and at times hair-raisingly narrow Kalalau Trail, carved into the cliff sides – the most thrilling way to take in the full panorama of peaks, sky and water is undoubtedly by sea kayak. Paddling its 17 miles in three sections – from Haena Beach Park  on the north shore to Polihale State Park  on the west, stopping overnight at the Hawaii State Park campgrounds of Kalalau and Milolii  –­ makes for a slow-paced and immersive experience. Kayakers can explore the island’s sea caves and hike into its valleys at their own speed, not to mention shower in waterfalls and fall asleep to the music of the waves under stars as bright as a meteor shower.

Napali Kayak, in the town of Hanalei on the north shore, offers multiday excursion packages, with a guide for at least the first leg of the trip plus ruddered double kayaks, seat backs, paddles, dry bags and life jackets. Day trips that compress the paddling into about six hours are also on offer. If the trip from Haena Beach to the first campground at Kalalau goes smoothly, the guide may allow kayakers to continue on their own down the coast. Kayakers should pack at least four days’ worth of personal supplies, food and water purification tablets as the water sources (waterfalls!) are unfiltered. And even if you do not usually get seasick, bring motion-sickness pills. The waves can be rough.

Just to be clear: this is not leisurely bay or river kayaking. The paddling is exhausting and can be extremely challenging depending on the conditions. Horror stories of sunburn, seasickness and overexertion populate review websites, and news stories about reckless kayakers who required rescuing dot the internet. But all that should not discourage healthy, reasonably athletic adults from taking a guide-led, well-prepared trip into Kauai’s true wilderness.

The itinerary starts at dawn just west of Hanalei, in Haena Beach Park, when the Pacific is its calmest. Once kayakers have paddled out past the break, the full expanse of the Na Pali coast comes into view. As far as the eye can see, impossibly tall cliffs rise majestically to the left, and the opalescent Pacific stretches out to the right. The cliffs fade from lush green nearby to reddish brown in the distance, and waterfalls stream down the cliff sides. The water here – clear enough for paddlers to see boulders that have fallen from the rock walls – is home to reef fish, flying fish, spinner dolphins and endangered green sea turtles who often swim directly underneath the kayaks. Lucky groups may even spot an endangered monk seal or a humpback whale.

Kalalau Beach beckons about seven miles ahead. Along the way, guides lead groups into sea caves that interrupt the coastline, where rivulets of mountain water form waterfalls that flow from the openings and waves crash against the walls. They point out wildlife and tell stories about the ancient Hawaiian warriors who once used Kauai as a training ground.

Arriving in the midday heat, Kalalau will look deserted; campers have retreated to sites amid the ridge of trees. At the west end of the beach, an icy-cold waterfall serves as water source. When choosing a spot to pitch your tent, pay attention to signs marking areas where tumbling boulders land. Night-time is punctuated by the sound of rocks skittering down the cliffs, courtesy of mountain goats nimbly climbing hundreds of feet overhead.

The vibe at Kalalau is like a rustic festival, a la Bonnaroo or Glastonbury. Barely clad campers with saltwater-tousled hair share just-picked mangoes and greet one another with a friendly “Mahalo” or “Howzit?” (Hawaiian slang for “hello” and “what’s up?” respectively). A path winds through the campsite, fringed by the impressive lodgings of residents who seem to have adopted this paradisiacal existence for the long term, shoring up their shelters with found objects and materials gleaned from the surrounding forests. They lazily sip beers and sway in hammocks nested in spots with primo shade and vistas.

Of the two campsites on the coast, Kalalau merits a longer stay. A cool morning is perfect for a hike into the Kalalau Valley, where soaring mango and guava trees impart shade. Afternoons can be spent snorkelling or, when the tide is out, exploring a desolate beach past the caves to the west where delicate arches of stone have been etched by the waves and mammoth boulders rise out of the water like whales. Dinnertime entertainment is watching a postcard-worthy sunset unfold as the light fades from orange to pink to purple to inky blue, the only demarcation between sky and cliffs the patchwork of stars in the heavens.

For the second leg of the trip, it is advisable to set out early before the tide comes in. More sea caves dot the five-mile route to Milolii camp, the largest and most impressive of which is the open-ceiling sea cave that looks like a mermaid’s grotto. A rock formation perfect for sunning and snapping photos juts from the centre of the cave’s pool, and its ocean-sculpted walls possess the organic look and feel of something submerged, which many of these caves are in the winter. The main challenge of this stretch is paddling around the curve of the island, where coral reefs require kayakers to fan out a few hundred yards from shore.

After navigating channel markers signalling the path through Milolii’s own coral reef to the beach, kayakers will find themselves in relative luxury, with an outdoor shower, a spigot for running water, outhouses and picnic tables. It is a peaceful, easy place to camp – like a castaway’s settlement, with a long abandoned-looking park ranger’s cabin – but there is not much to explore. Because Milolii is located on the dry western side of Kauai, there is also less shade. Still, the snorkelling at Milolii makes for an eventful afternoon and it is fun to gather coral and shells on the sand.

The final part of the trip is a five-mile jaunt. Past Milolii, the cliffs grow abject and adobe spare. There are no more sea caves to explore, no more waterfalls – just the promise of civilisation glimmering on the beach at the Na Pali coast’s end point: Polihale State Park. Then, the only thing left to do is drive counter clockwise back around the island, watching its beautiful coffee plantations go by. Consider a pit stop for a Hawaiian-style shave ice  – the local frozen treat of choice, consisting of flaky, thin-shaved ice flavoured with a rainbow of syrup possibilities, atop a foundation of macadamia-nut ice cream – at the original Jo-Jo’s (9899 Waimea Road; 808-431-4840), in the town of Waimea. For Na Pali coast veterans who have braved one of the US’s wildest adventures, such a cold treat is a just reward.

Mid-May through September is the time to kayak the Na Pali coast, because winter swells up to 50ft high make the excursion unsafe in the colder months. Napali Kayak offers guides and equipment for hire; from $380 per person, including equipment, a guide to Kalalau and transportation from the shop to the put-in point at Haena Beach Park and from Polihale Beach Park back to the shop at the end of the trip..

Camping permits for Kalalau and Milolii should be secured at least two months ahead of travel through Hawaii’s Department of Land and Natural Resources ($20 per person per night for Hawaii non-residents).