Kauai

27 km of fluted cliffs plunging over 1,000 metres into the Pacific, with hanging valleys and sea caves, seen only by catamaran from Port Allen or by helicopter from Līhuʻe.

💡 Choose a trip between May and September, when the north swell is low: in winter, the boats often stay well away from the cliffs or cancel. A catamaran with snorkelling costs about $180-250 per person, or €155-215, and a helicopter flight of about an hour $300-450, or €260-390.

At the end of the northern road, the reef-sheltered lagoon of Kēʻē beach and the start of the Kalalau Trail, open to reservation holders as far as Hanakāpīʻai beach and its waterfall.

💡 Non-residents must book entry and parking, or the shuttle from Hanalei, up to 30 days ahead on the state parks website: summer places go within minutes. Never swim at Hanakāpīʻai, where the currents have drowned dozens of hikers. Price: $5 per person, about €4, and $10 per parking slot, about €9.

At the gateway to Nā Pali, ancient stone taro terraces, Polynesian-introduced plants and rare native species along an intact stream, on a 1.2 km loop with valley and ocean views.

💡 Book online, up to 30 days ahead, to guarantee your place in a very limited car park. The garden opens Tuesday to Saturday and its gate closes at 2.15pm. Passengers on the North Shore Shuttle enter without a reservation and pay $5 less, about €4. Bring good shoes for the steps. Price: $30 from age 13, about €26, free for under-13s accompanied by an adult.

A clifftop peninsula crowned by a 1913 lighthouse, a national seabird refuge with red-footed boobies, frigatebirds and Laysan albatrosses, where dolphins and whales are often seen offshore.

💡 Open Wednesday to Saturday, from 10am to 4pm, with a compulsory timed reservation on recreation.gov for ages 16 and over, released 60 days ahead. Bring binoculars. Price: about $10 per adult plus $1 booking fee, about €10; the America the Beautiful pass is accepted.

Hawaii's only navigable river, flowing past ancient Hawaiian temples, explored by boat to the fern-lined Fern Grotto or by kayak up to the trail for Uluwehi Falls.

💡 Hire a kayak in the morning, as the wind picks up in the afternoon, and check with the rental firm about access to the waterfall trail, which closes after heavy rain. Price: the state park charges non-residents $5 per person and $10 per vehicle, about €4 and €9, plus kayak hire.

A garden of green rooms, pools and statues running down the Lāwaʻi valley to the sea, visited only with a guide, where the giant Moreton Bay figs starred in Jurassic Park.

💡 Book on the National Tropical Botanical Garden website: tours leave at set times and are often fully booked. Arrive 30 minutes before departure, in closed shoes or strapped walking sandals, which are required. The neighbouring McBryde Garden, which brings together the largest collection of native plants in Hawaii, can be visited on your own from the same centre. Price: $65 per adult, about €56, and $32.50 for ages 2 to 12, about €28.