South of Makena Beach, the road fades away into a vast territory of black-lava flows, the result of Haleakala's last eruption and now a place for exploration on land and below the water. Before it ends, the road passes through the Ahihi-Kinau Natural Area Reserve, an excellent place for morning snorkel adventures. All wildlife, vegetation, coral, lava rock formations, and archaeological sites are highly protected under state law, which means that removing or disturbing items is prohibited, as is fishing. It also means you should tread carefully over this culturally important landscape. Reserve staff advise that you stay on the trail and adhere closely to the signage, as you will be hiking through the remains of one of Maui's ancient villages. Adjacent to Ahihi-Kinau is the Keoneoio archaeological district, aka "La Perouse" bay, where the start of the Hoapili Trail can be found.
The WWII-era military ordnance deposited between 1945 and 1946 has prompted concerns and recommendations
by the U.S. Army Corps of Engineers for continued closure of the less accessible areas of the reserve—a yellow rope delineates the open and closed areas of the reserve, and enforcement is taken seriously. The ancient remains of the Hawaiian village of Maonakala are found along the coast and are inside the closed area for their protection. Kalaeloa and Mokuha, aka "aquarium" and "fishbowl," are also within the closed area. As of this writing, the closed areas of the reserve are scheduled to reopen in August 2016. Parts that remain open include the coastal area along Ahihi Bay, such as Waiala Cove and Kanahena Beach, aka the "Dumps" surf break.
The unimproved Kanahena parking area is open from 5:30 am to 7:30 pm. Do not bring valuables in your vehicle and do not leave keys unattended on the beach.
Limited (or no) cell phone service exists at and beyond the reserve. There is little shade, so bring a large supply of water, a hat, and sturdy footwear.