Spiny dogfish are benthopelagic, meaning that they are found just above the bottom of the ocean. They are found from the surface to depths as deep as 1,460 metres. Spiny dogfish can be found in brackish water, but prefer seawater, and are commonly found in waters with the temperature of 7-15 °C. Spiny dogfish are found inshore and offshore, over continental and insular (island) shelve, and upper slopes. They are often found in enclosed bays and estuaries. They have been reported to enter freshwater but cannot survive there for more than a few hours.