Hwy. 50, Waimea
Your rental car contract will prohibit you from accessing this beach—and should you attempt it, you'll understand why. The road is terrible, but the beach at its end is incredible. At 17-miles long, its one of Hawaii's longest beaches and it is vast and stunning and more or less empty. It abuts the Napali Coast and shares those epic views. Similarly, it faces the open ocean and the waves are intense, making the water only safe for strong swimmers. Most visitors come to walk the beach.
Waimea Canyon State Park Hike
Waimea Canyon Dr., Waimea
You can hike your way to an 800-foot, two-tiered waterfall, which is known as the Grand Canyon of the Pacific. Take the extra time to hike the Canyon Trail: It brings you through a forest until you reach the exposed ridge, where you’ll be greeted by an incredible view of the canyon’s monumental rock formations (take care, as there are no guardrails). Hike up from there to a peaceful pool above Waipo’o Falls; the whole trek takes a few hours roundtrip.
Waimea Plantation Cottages
9400 Kaumualii Hwy., Waimea
So there's nothing particularly splashy about Waimea Plantation, but that's precisely the point. The beach isn't particularly spectacular either, but that's no bother, either. These sprawling cottages, which occupy the grounds of a former sugar plantation, are ramshackle and adorable, and exactly what belongs at the beach. They're also perfect for a family, as they come equipped with kitchens and all that jazz—all the better for enjoying the fresh tuna sashimi from the nearby Japanese grocery store, Ishihara (seriously, it's insane). There's incredible surf to swim in to the west of the cottages in the naval base, and it's close to the bigger resorts on Poipu. The North Side and Princeville are a bit of a drive, but it's worth your while to hike along the Western side of Kauai: it's one of the more spectacular views in the world.