The atoll is roughly four-sided and nearly across in the east–west direction, and averages about north to south. The reef is more submerged and broken into several broad channels along the west side. Small islets are found on reef sections between these channels. The atoll reef is continuous but almost without islets along the north side. In the northeast corner, the reef is some across and with only scattered small islet development. Thus, the lagoon of Butaritari is very open to exchange with the ocean. The lagoon is deep and can accommodate large ships, though the entrance passages are relatively narrow.