The Kalalau Trail, Hawaii's most famous hiking trail, extends for 11 miles along Kauai's Napali coast. A permit is needed to hike the length of the trail as people normally camp in the beautiful Kalalau valley. This trail is for experienced and serious hikers only. Casual hikers can do a great 30 minute walk up the path to see a view of the coast and also Ke'e beach, or do a 2-4 mile hike to Hanakapi'ai beach (2 miles in) or Hanakapi'ai falls (4 miles in). Both of these hikes are challenging and require preparation, taking 3-5 hours round trip depending on whether you go to the falls or not. And remember, you can't swim at Hanakapi'ai beach to cool off (the currents at this beach are exceptionally dangerous)..