This is a NOT to be missed spectacular area of Kauai. This canyon was dubbed the "Grand Canyon of the Pacific" by Mark Twain, and one look lets you know why. They definitely do look eerily similar. The layers, colors, and waterfalls are simply gorgeous.
To get there, the "book" (Ultimate Kauai) tells you to take Waimea Canyon Road (Rt 550) instead of following the signs to a later road. The book is right—the views ARE better from Waimea Canyon Rd—we tried both. Take the other road (Rt 552) on the way back if you're curious.
The road is paved and an easy drive. There are several lookouts along the way (once up) to pull over and gawk. Stop at more than one, the view changes—sometimes letting you see spectacular waterfalls pouring into the canyon.
A couple of the bigger lookouts that the tour buses use have restrooms. They also often have locals selling various fresh and dried fruit. They aren't cheap, but seldom is food cheap in Hawaii.
Look to the south and you see the ocean and Niihau—a privately owned Hawaiian island. Look to the north and you see the Alakai Swamp—the highest swamp in the islands—and the place that we chose to hike in (see separate entry). For those wanting other hikes, many are available.
Continuing on the road past the main canyon lookouts, you'll come to the Kokee Museum—a small place, but with some neat displays of the canyon. It's free. Using the same parking lot is the Kokee Lodge—the only place to EAT around here—you HAVE to try their cornbread, it was AWESOME. The Kalua Pork sandwich was tasty too...
Continuing your drive you come to the end of the road with a final lookout—not of the canyon, but of the green Kalalau Valley on the Na Pali Coast. This view is OK, but a better one is a hike down the closed road another mile or so. I'm not sure why they closed the road to that lookout, perhaps to encourage more people to hike? Many people do the hike. It's all paved, but there are hills, so decide for yourself if you want exercise.
For a brief visit of the Canyon, you can use a tour bus. However, we never saw any of them go all the way back the road and they only stop at the lookouts big enough to handle the buses. As is common, we recommend you rent your own car and explore at your own pace, stopping where YOU want to for as long as YOU want, and having the freedom to hike!