Maui has many volcanic rock formations along its coastline. Having driven all around the island, I can say that this is the only one I was compelled to climb from the moment I saw it. Pu‘u Koa‘e (also called Sugarloaf), the summit of Kahakuloa Head, stands 636 ft. from ocean to summit, with vertical cliffs on all sides but the south; the southern aspect is still steep however. From the summit, one can see most of Maui's northern coastline, Haleakala, and if you like the color blue, you will be completely enveloped by it.
More information, as well as pictures of the west face, can be found here: Hawaii Web
Pu‘u Koa‘e lies on the north-eastern shore of West Maui, a half mile to the NE of the village of Kahakuloa, and guards the east side of Kahakuloa bay. Take Kahekili Highway (340) from which ever direction, but keep in mind that most of the highway south of Pu‘u Koa‘e is a single lane road and may take you more that hour to get there by car from Kahului. The formation is past the "mile 14" marker going southeast; the parking lot is due south and overlooks the saddle between it and Pu`u Kahulianape.
There is no obvious red tape. There is an open gate at the parking lot that leads into the area. There are several well traveled trails around this area; there is a decent use trail up to the formation as well. There were no signs posted.
When To Climb
Climb when it is not raining, that is all I can say. There is significant exposure on the easiest route.
"It occurred to me that anyway one more Sunday was over, that Maman was buried now, that I was going back to work, and that, really, nothing had changed."
--Meursault in 'The Stranger'