The northeast coast of Kauai—from Anahola to Princeville—has more than a dozen hike-to beaches, by far the best run of wild coast in Hawaii. One of the most scenic is Secret Beach near Kilauea, which isn't a big secret these days. But it is comprised of three separate beaches about a mile long in total, so privacy is not a problem. At the far end of Secret Beach is the Kilauea National Wildlife Refuge, whose historic lighthouse marks the northern-most spot among the major Hawaiian Islands.
Local dudes and dudettes like the multi-tiered shorebreaks at Secret, perfect for jivving on a short board. But ask advice before venturing out, since near-shore rocks and rip currents make this a surfing beach beginners should avoid. While watching the waves, keep an eye out for spinner dolphins who frequent this bay, and for whales who frolick offshore during the winter.
One end of Secret Beach (to the left where the trail drops to the sand) has a reef with pools perfect for soaking—and also perfect for getting Maytaged by foaming surf. The waves here are normally a lethal hazard, so stay back and give it respect.
Kauai Trailblazer has details on all the beaches for this coastline—which should be at the top of the list for independent travelers.