Map - Rangiroa

Rangiroa (Tuamotuan for 'vast sky') or Te Kokōta (Cook Islands Māori for 'the Hyades star cluster') is the largest atoll in the Tuamotus and one of the largest in the world (smaller than Kwajalein in the Marshall Islands and Huvadhu in the Maldives).

It is in French Polynesia and is part of the Palliser group. The nearest atoll is Tikehau, 12 km to the west. It is about 355 km northeast of Tahiti. Rangiroa is home to about 2,500 people on almost 80 km2. The chief town is Avatoru, in the atoll's northwest.

The atoll consists of about 415 motus, islets and sandbars comprising a total land area of about 170 km2. There are approximately one hundred narrow passages (straits or passes), called hoa, in the fringing reef. The atoll has a flattened elliptic shape, with 80 km in length and a width ranging from 5-32 km. The width of land reaches 300-500 meters wide and its circumference totals up to 200 km. The lagoon has a maximum depth of 35 m and its surface is 1446 km2. It is so large that it has its own horizon. Due to its shallow depth, the currents that come in and out through the passes, together with the winds, can sometimes create interior storms.

Because of their large size, and the existence of only two passes, each high tide creates a strong incoming current, while each low tide creates a strong outgoing current within the two passes. While flowing inward through Tiputa Pass, nearly 200 individual sharks will gather at the entrance to the pass, at a depth of 50 meters. Led by the strong current, sharks can remain motionless. Divers are able to observe them without difficulty. Large manta ray, green sea turtle, and humphead wrasse are also seen. During summer (December-March), tiger and hammerhead shark are present. In January, large numbers of stingray gather in the Tiputa Pass, as do the hammerheads that feed on them.