Moananui Islet is an islet in Penrhyn Atoll (Tongareva) in the Cook Islands.
The main village of the atoll, Omoka, is situated on Moananui Islet. The islet has a small airstrip.
Coordinates: 8°59′S 158°04′W / 8.983°S 158.067°W / -8.983; -158.067