The Wailua River is said to be the only navigable river in Hawaii (depending on how you define navigable). In the case of taking a boat a few miles inland to a lovely mecca of ferns and tropical plants - the Fern Grotto, it means Wailua River.
The first road on Highway 56 after pulling off Highway 580 is the road to Smith’s Tropical Paradise (that’s the best name to give it, there doesn’t appear to be a real name for the road). There will be a ticket booth on the right where you’ll want to stop and purchase your ticket for the trip up the Wailua River.
The price, as of this writing, was only $25/adults ($12.50/kids) and well worth it. Tours depart frequently throughout the day and are run by Smith’s 117 Motorboat Service. You can also opt to kayak up the river, but the tour is a much easier route for most visitors.
This ticket booth should have a schedule of tours for each day, except Sundays. The boat will take you three miles up the Wailua River and make a visit to the famous Fern Grotto. The Grotto has undergone major renovations over the years; it was damaged pretty badly by Hurricane Iniki in 1992.
The Fern Grotto is a large natural amphitheater with hundreds of ferns draped from it. The gardens leading up to the amphitheater are full of tropical plants and fl owers, including the incredible split-leaf philodendrons or swiss-cheese plant - one of our favorites. It is actually native to Mexico, but it makes for a lovely addition to Hawaii's jungles.
The tour is about 30 minutes up the river in the large passenger boats, usually accompanied by entertainment, mele (song), and dance. The visit to the Grotto itself is usually between 30-45 minutes. The Fern Grotto is also a popular place for weddings, and many ceremonies take place there, several on the same day in some instances.
Once you’ve taken the tour and experienced the Grotto, turn left out of the dock parking lot. Smith’s Tropical Paradise is located beside the dock a little bit down the road and is worth a visit if time permits.