The Smith family has been running this cruise since 1946, and it’s stayed exactly as unhurried as it sounds. A covered riverboat carries you up the Wailua River — Hawaii’s only navigable river — while a live musician plays and tells the stories behind the landmarks you’re passing. About 80 minutes round trip, most of it spent gliding past jungle rather than doing anything strenuous.
The destination is the Fern Grotto itself: a natural lava-rock cave with ferns cascading from the ceiling, cool and green and quiet after the open water. It’s a favorite for grandparents and small kids alike precisely because there’s no hiking involved — you sit, you watch, someone else does the paddling.
Boats depart from Wailua Marina, a straightforward ten-minute drive from the condos. Mornings tend to run calmer water and better light for photos, and the cruise operates rain or shine, which makes it a solid backup plan alongside the museum if the forecast looks iffy. Book ahead in peak season — the boats aren’t huge, and this is one of the island’s longest-running tours for a reason.
