 Maupihaa atoll is roughly 8 km in length and contains a lagoon that is up to 40 m in depth and is surrounded by submerged reefs on three sides.The atoll's outer reefs are continuous except for a small passage on the western side of the atoll.The eastern side consists of a narrow, thickly vegetated, islet (Motu Maupihaa) and a number of smaller islets bring the total land area of Maupihaa to 2.6 km².