Mikomoto island is a small uninhabited island consisting only of reefs, about 10 km off the southeast coast of the Izu Peninsula, Japan. The island is the point where ships from the west turn to head toward Tokyo Bay. The waters around the island are full of shoals and reefs, and the currents are fierce, so the island has long been known as an important and difficult navigational point. The symbol of the island, Mikomotojima Lighthouse, is the oldest stone lighthouse still in service in Japan. It still plays an important role as a lighthouse that marks the entrance to Sagami Bay and Tokyo Bay. The island is located on the border between Sagami Bay and Suruga Bay, and greatly influenced by the Kuroshio Current, one of the world's largest tidal currents. Therefore it is very tidal, and also known among fishermen and anglers as a good place for big game fishing.