Smith's Motor Boat Services is now the only way to legally see the grotto, recently refurbished under a state tourism grant. You can access the entrance with a kayak, but if boats are there, you won't be allowed to land. Smith's Tropical Paradise and the Fern Grotto tour are located in the
Wailua Marina State Park on the east side of the island. Once you’ve
turned off the highway, just follow the drive all the way back to the
parking area.
From the North (Hanalei, Princeville, Kapaa):
Take Hwy. 56 South through Kapaa to the Wailua River. Go past Kuamoo
road, over the river, and take the first right into the Wailua Marina
State Park.
From the South (Waimea, Poipu, Lihue):
Take Hwy. 56 North from the Lihue airport. A mile after the Wailua Golf
Course, watch for Marina signs and the beach on the right. Just before
crossing the Wailua River bridge, turn left into the Wailua Marina
State Park.
Daily departures 9:30-3:30.