 Bass Strait is approximately wide and long, with an average depth of .The widest opening is about 350 km between Cape Portland on the North-Eastern tip of Tasmania and Point Hicks on the Australian mainland.Jennings' study of the submarine topography of Bass Strait described the bathymetric Bass Basin, a shallow depression approximately wide and long (over in area) in the centre of Bass Strait, a maximum depth is the channel between Inner Sister and Flinders, which navigation charts indicate reaches .