Tied islands, or land-tied islands as they are often known, are landforms consisting of an island that is connected to land only by a tombolo: a spit of beach materials connected to land at both ends. St Ninian's Isle, in the Shetland Islands off the north coast of Scotland, is an example of this; it was once an island but is now linked to the Mainland. Other examples include: Maury Island, Washington in the Puget Sound, Coronado, California and Nahant, Massachusetts in the U.S.; Barrenjoey, New South Wales in Australia; Wedge Island in Western Australia; Cheung Chau in Hong Kong and Davaar Island, Campbeltown, Scotland.
The Isle of Portland is also described as a tied island, although geographers now believe that Chesil Beach (which connects the island to the mainland) is a barrier beach that has moved eastwards, rather than a tombolo, which would have been formed by the effect of the island on waves.
Paniquian Island (also known as Isla Boquete) is a tied island in Puerto Galera, a popular tourist destination in the Philippines. The island is connected to the main island of Mindoro by a small tombolo that is only submerged a few times per year.