Between mile markers 13 and 14 on the Hana Highway you will have a chance to visit Honomanu Bay. There are two roads that lead to the beach.
The first is about a half-mile beyond the 13 mile marker - but this dirt road brings you out on the wrong side of the beach (the stream will cut you off from the remainder of the shoreline). The other access road is available just beyond the 14 mile marker. This route is much muddier, steeper, and 4x4 may be required at times so you might have to walk to the beach instead. Taking your car off-road is a violation of your rental agreement anyway.
Like many beaches in Hawai‘i, the amount of sand can vary from the winter to summer months. In the winter months the beach can be mostly small rocks and boulders. Whereas, in the summer the sand will return. The beach is frequented by surfers, especially in the winter months. Swimming is ill-advised due to rough surf. In our opinion, the best way to view this bay is from above (at mile marker 13 or one of the upcoming lookouts).