Bass Strait is a sea strait separating Tasmania from the south of the Australian mainland. It was discovered by Europeans in 1798 by Matthew Flinders and named after explorer George Bass.

Approximately 200 (?) kilometres wide at its narrowest point, it was almost dry during the last ice age. It contains many islands, with King Island and Flinders Island home to substantial human settlements.

Like the rest of the waters surrounding Tasmania, it is notoriously rough, with many ships lost there during the 19th century. In 1859 a lighthouse was completed on Wilsons Promontory to help protect shipping passing that point.