For a quick, scenic hike to the bay, take the Na Ala Hele trailhead on the makai (seaward) side of the road, along the Pepeʻekeo 4-Mile Scenic Drive. From Hilo, turn onto the scenic drive, go about 1.75 miles and look for a sign marking the trailhead. Parking is tricky, but there's a small turnout just north of the sign.
After a 10-minute hike down a slippery jungle path, you'll come to a finger of lava jutting into the sea. A spur to the right leads to a couple of small waterfalls and a cove. Continuing straight brings you to the diminutive bluffs overlooking the batik blues of Onomea Bay. Hawaiian monk seals have been sighted here.