Upi Bay, on the southeast coast, is an extraordinary landscape: the water is flat calm and shallow, and the bay is studded with large rounded coral formations rising from the surface like green islands — often compared to Halong Bay. The standard way to see it is by traditional outrigger pirogue, paddled by a local Kanak guide.
The trip across the bay takes about 90 minutes each way and typically ends at the trailhead for the Piscine Naturelle, so most visitors combine the two into a half-day excursion. Guides operate from the beach near the south end of the island; look for signposting or ask at your accommodation. Tours run most mornings and are weather-dependent.