Muriwai, also called Muriwai Beach, is a coastal community on the west coast of the Auckland Region in the North Island of New Zealand. The black-sand surf beach and surrounding area is a popular recreational area for Aucklanders. Gannets nest there in a large colony on the rocks.

Muriwai is approximately 17 km west of Kumeu, 42 kilometres northwest of Auckland city, at the southern end of an unbroken 50 kilometre stretch of beach which extends up the Tasman Sea coast to the mouth of the Kaipara Harbour. One of several popular beaches in the area (others include Piha and Karekare), it experiences a population explosion in summer when Aucklanders head to the sea. It is in the Rodney Ward of the Auckland Region.