Haʻena
The most dramatic coastal trail in the United States — 11 miles of Na Pali cliffs with no road access and no way out except back the way you came. Two day-hike options: (1) First 2 miles to Hanakapiʻai Beach (1–2 hours each way) — this alone delivers clifftop views that rival anything in Hawaii; the beach at the end is a remote black sand cove, swimming prohibited due to shore break. (2) Continue 3.5km inland from the beach to Hanakapiʻai Falls (add 3 hours round trip) — a 91m waterfall in a jungle amphitheater. Plan 5–6 hours total for beach + falls. Trail is extremely muddy after rain; add 30–60% to time estimates and wear closed-toe shoes with grip.
Reservation required at gohaena.com — same permit covers Ha'ena State Park entry and Kalalau Trail access. $5/person + $10 parking or shuttle. Book exactly 30 days ahead at 6am HST; slots go in minutes. Shuttle from Waipa Park & Ride in Hanalei is the recommended option (parking at the trailhead is extremely limited). No food services near the trailhead — bring a full daypack: water, food, first-aid, rain gear.
Trail is open year-round but conditions vary enormously. Dry summer (May–September): manageable mud. Wet winter: sections can become dangerously slippery. Never hike beyond mile 2 in heavy rain — flash floods can strand hikers. The ocean at Hanakapiʻai Beach is lethal year-round.