Yubu is a tiny island, about 2 km in circumference, sitting just off the east coast of Iriomote. It is a private nature park — a long footpath wandering through hibiscus, bougainvillea, palms, and a small butterfly garden, ending at a beach with views back to the main island.
The point is not the island itself but the way you get there: in a wooden cart pulled across the tidal channel by a water buffalo. The whole excursion takes maybe 90 minutes and is unashamedly touristic, but in this case the cliché is also the experience.