Lot's Wife (孀婦岩, Sōfu-iwa or Sōfugan, "Widow Rock") is a volcanic desert island located in the Philippine Sea approximately 650 kilometres (400 mi) south off the coast of Tokyo, at the southernmost tip of the Izu archipelago, Japan.

The island is a basalt pillar with sheer sides, the only visible portion of a submarine volcanic caldera extending 2.6 kilometres (1.6 mi) south-east at an average depth of 240 metres (790 ft).

Due to its shape and heavy seas, it is almost impossible to disembark on the island, although attempts have been made by rock climbers successfully in 1972 and 2003 (though several accidents have been registered).

On April 9, 1788, British merchant sailor John Meares sighted what he came to describe as “the most marvellous thing” he had ever set his eyes on, a small island he and the ship’s crew decided to baptize as Lot's Wife, referring to the Book of Genesis 19:26.

[2] During the Pacific War, Sofu Gan was used by US Navy submariners as a reference marker for calibration of instruments as they entered Japanese waters.