The northeast shore of Kauai has a couple dozen undeveloped beaches, but if you can only see one, head for Larsens. It's a three-fer, really, since the first long stretch is followed by two more beaches that are separated by low-lying points.
Flip flops will aid on the short trail down from the parking area, but barefoot is the way to go thereafter.
One of your beach mates is bound to be a Hawaiian Monk Seal, since they like to sunbathe here. Be Aware: Good manners and the law require keeping a distance of 100 feet from these endangered mammals—the only ones native to the Islands (unless you count a species of bat). This shot was taken with a telephoto.
Sea turtles, less common on Kauai than the other islands, also join the party at Larsens'.
Journey's end is Kepuhi Point, where waves do battle with a sculptured point. Guess who's going to win.
Laysan Albatrosses nest in the ironwood trees on the hills above the shore. Of course, this chick is earthbound, but mom and dad are the B-1 bombers of bird world, able to fly far across the seas without rest. But even the adults need a good run to make their awkward takeoffs (hence the nickname 'gooney birds'), making these creatures vulnerable to dogs. Albatrosses are not freaked by people—they nest on the golf course fringes in Princeville—but you want to give them space.
Larsens is known as a treacherous swimming beach, but you can find safe places to get wet. Kauai Trailblazer has the details for visiting here, as well as the other unsigned, unpopulated beaches up and down the coast. Be Aware: Although nudity is against the law on all beaches in Hawaii, you may see a naked person tucked into the backshore along the way on some days.