Lyttelton Harbour, or Whakaraupō, is a large, sheltered saltwater harbour on the Banks Peninsula near Christchurch. It is a drowned volcanic crater, formed by the collapse of the ancient Lyttelton Volcano, which gives it a unique and deep basin structure. The harbour is protected by a substantial breakwater at its entrance, providing calm waters inside. The inner harbour features extensive intertidal mudflats that are exposed at low tide, creating a dynamic environment of shallow flats and deeper channels. The surrounding Port Hills form a dramatic backdrop. The harbour is managed as a Mātaitai Reserve, a customary fishing area, which imposes specific regulations on all fishing activity.