Tumbi Umbi is a mostly semi-rural suburb of the Central Coast region of New South Wales, Australia, located northwest of Bateau Bay. It is part of the Wyong Shire local government area.
It is a somewhat distributed community on the shores of Tuggerah Lake and associated with the creek that feeds into that body of water. In Aboriginal times the description "A place of much water" accurately described the swamp land that has now been extensively drained and populated with housing, industrial estates, a school, Mingara Recreation Club, Mingara One Fitness and Aquatic Centre, a pistol range and Glengara Retirement Village.