Take the green serpentine road to Hana and park just past the community center (Maui Trailblazer has the details.) A short trail hugs an eroded hillside among ironwood trees to a narrow section, where you can drop like Santa from up on the house top to the hidden cove that is Red Sand Beach. Cinder from a volcanic cone adds the color. A ragged inshore reef provides a calm area for swimmers, though wave action can be a factor in the winter.
A few precautions: During heavy rains, the trail is best avoided, especially the one narrow section. Also, be prepared to see a nude sunbather or two at this beach, even though nudity is prohibited on all Hawaiian beaches.