Naukacuvu, also known as Agate Island, lies in Fiji's Yasawa archipelago and is located off the western coast of Viti Levu, Fiji's largest island. The island was named after Thomas Agate who was the designated portrait and botanical artist for the United States Exploring Expedition of 1838–1842.

There is a small light on Agate Island, just inside the harbour, to guide mariners between the islands and into the harbour, and a larger light on the tip of the peninsula forming the eastern side of the harbour to serve vessels sailing along the lake between Thunder Bay and Sault Ste. Marie.

Paradise Cover Resort is located on this island.