Motu One, Coral atoll in the Leeward Islands, French Polynesia

Motu One is a coral atoll of the Leeward Islands in the Society Islands, French Polynesia, lying 550 km northwest of Tahiti and 72 km northeast of Manuae. Its reef encloses a lagoon without a pass, and low wooded sandy islets cover all sides except the southern one. The atoll's land area totals 2.3 km² across one larger and five small islands.

The atoll received its name in the early 1800s when Otto von Kotzebue designated it after Russian explorer Fabian Gottlieb von Bellingshausen during Pacific expeditions. This naming reflects the era of European exploration and the mapping of remote island territories in the region.

The name translates to "Island of Sand" in Tahitian, reflecting how Polynesian people traditionally named locations based on the natural features they observed in their landscape.

Motu One lies 550 km northwest of Tahiti and 72 km northeast of Manuae, its nearest neighbour, in the Leeward Islands. The reef encloses the lagoon completely, with no pass, so no boat can enter the lagoon; the atoll is uninhabited and has no facilities. Plan any approach from outside the reef with a supply of drinking water and shelter of your own.

Motu One is also called Papa Iti or Temiromiro in Polynesian, and some sources spell its alternate European name Bellinghausen while others write Bellingshausen. The atoll is uninhabited today and serves as a breeding and resting site for several bird species; the green sea turtle lays its eggs on its shores.