Longstone is small settlement on the island of St Mary's, the largest of the Isles of Scilly, England.

Longstone is located inland, at the approximate geographic centre of the island.

[1] In Longstone is Carreg Dhu Garden, a publicly accessible 1.5 acres (0.61 ha) garden set in a former quarry, maintained by volunteers.

[2] On the site of the former Heritage Centre, which was closed and put up for sale in the summer of 2011,[3] a cafe was opened in 2018, with an extension called Longstone Lodge opening as a hostel (sleeping accommodation in a private room or a dormitory, with shared kitchen and living area).

This article about a location in the Isles of Scilly, Cornwall is a stub.