Amazingly, this secluded black-sand beach belongs to Kekaha Kai (Kona Coast) State Park. Although there's no shade and it's too rocky for swimming, its natural beauty rewards those who make the effort to visit (which is usually some local fishingfolk). To reach this small, dark treasure on foot, head south along Mahaiʻula Beach and either follow the road or the coastline while making toward a lone tree.
With a 4WD, turn left at the road junction by Mahaiʻula Beach, drive south for about 1000yd until you reach a path marked by white coral, then get out and hoof it as the lava becomes too rough.