Blowhole

Blowhole may refer to:
 * Blowhole (anatomy), the hole at the top of a whale's or other cetacean's head
 * Blowhole (geology), a hole at the inland end of a sea cave
 * Kiama Blowhole in Kiama, Australia
 * The Blow Hole, a marine passage between Minstrel and East Cracroft Islands in the Central Coast of British Columbia, Canada
 * Blowhole Diversion Tunnel in Victoria, Australia
 * A type of casting defect in metalworking