The advantage of Wailua Falls is that you do not have to earn it. A few miles past Hana, beyond the point where many visitors turn around, the road crosses a bridge, and the waterfall appears beside it: a clean drop of roughly eighty feet into a green pool, fed by a stream that never seems to run dry. There is a pull-off, a short path, and usually a small crowd with cameras. After hours of focusing on bends and bridges, it makes a welcome and easy reward.
The setting is lush even by Maui standards. This side of Haleakala catches the full force of the trade wind rain, and the slopes above the road hold dense forest of guava, hau, and fern. The water that comes over the lip has fallen on the mountain, collected in streams, and arrives here after a short, steep run. The volcanic rock under it was laid down in successive flows, and the stair-step shape of the falls shows how the stream has cut through layers of different hardness over time.
Wailua Falls is on the road toward Kipahulu and the Haleakala national park coast, and beyond it the road is a mixed bag. Stretches are narrow, and the surface can be broken, with one-lane sections where you simply have to read the corner and give way. The local drivers know it well and are not in a hurry. Do not expect fuel anywhere out here. Hana, nine kilometres back, has a small station of limited hours, and the sensible riders carry enough to reach Kula or return to Paia without worry.
Come in the morning if you want the pull-off to yourself, or in a fresh wet spell when the falls are at their loudest. Swimming below the falls is possible for some people but the path is steep and slippery, and rocks fall and flash floods happen, so be careful and read any signs. Bikes should be parked well out of the traffic lane. Because the road here is narrow and visibility short, step across with attention, and keep your helmet and gear close. Then go on south, with the road running dry and wide-skied beyond Kipahulu.