Every side of the island offers a wealth of scenic beauty, from towering cliffs and waterfalls to beaches that wrap around the island. And if you will are looking for a more "island" ambience, Kauai is much less resort-y than Maui or Waikiki in Oahu.
While a week is ideal for a Kauai vacation, many travelers combine Kauai with another Hawaiian island like Maui or Oahu, spending 3 or 4 days in Kauai.
Admiring the breathtaking beauty of the Na Pali Coast is one of the best things to do in Kauai. There's no road, so you can only see it from the air or from the water, or by hiking in.
Waimea Canyon, on the island's west side, is known as the "Grand Canyon of the Pacific." Look for Waipoo Falls, on the canyon's far wall: it is a dramatic two-tiered 800-foot waterfall!
Poipu Beach, on Kauai's south shore, is known as one of the most beautiful beaches in Hawaii. In the evening, you may see Hawaiian green sea turtles come to shore here.
Kauai is known for its many waterfalls, and on the island's east side, you can drive up to view the double cascades of Wailua Falls, and nearby Opaekaa Falls.
Charming towns like Hanalei are perfect for browsing shops and galleries, and enjoying refreshing Hawaiian shave ice. You'll find food trucks and many must-visit restaurants as well.