In a nutshell: A drive-up stop, one waterfall and pool are right next to the road. The second, larger waterfall and pool just upstream are impressively beautiful, and tragically underrated by other guidebooks.
Minuses: Unpredictable flow; also unpredictable visitor count (can be packed or empty, with no rhyme or reason.)
Sound-bite: “This is all I wanted to do in Hawaii.”
A popular, user-friendly (but frequently under-rated) stop on the Road to Hana. The reason this is so underrated by the other guidebooks is that they came to see it on the wrong day. The water source is heavily tapped and diverted above and these falls can be essentially “turned off” by EMI to feed thirsty sugar plantations. You can tell if this is worth a stop by looking at the waterfall closest to the road. If it is flowing, then you’re in for a treat.
The first waterfall is literally steps from the road, and has a beautiful pool tailor-made for swimming. The bigger second waterfall has multiple places to sit at the bottom and let the water fall on you. The last time I was there, a family was sitting under the waterfall, and I overheard the father blissfully claim “this is all I ever wanted to do in Hawaii.” I don’t know if I personally would be satisfied with just Waikamoi – but it is a really sweet place, that is so easily accessible without any serious hiking, that for someone doing an unplanned drive-thru, it could be the nicest waterfall they swim in.
Getting to the second fall requires a scramble up a (usually) mostly-dry stream bed – but unless the water is raging, it is pretty easy (and if the water is raging, don’t even try it!)
View Waikamoi Stream & Waterfalls in a larger map