Waikato Regional Council is responsible for managing the coastal marine area that extends from the high water mark (mean high water springs) to 12 nautical miles offshore. This area includes the west coast from Mokau in the south to Port Waikato in the north, and on the east coast, the Firth of Thames and the Coromandel Peninsula. The Waikato CMA covers over 10,000 km2 in area, includes about 1,150 km of shoreline and the water depth ranges from 0 to 500 m. The Waikato coastal environment includes the CMA and the land that is close to the coast and influenced by the sea (e.g. sand dunes, the splash zone).
Habitats and ecosystems in the Waikato coastal environment are diverse and highly valued for recreational, commercial, and cultural reasons. The Waikato coastal environment on the east coast is part of the Hauraki Gulf Marine Park, and on the west coast is part of the West Coast North Island Marine Mammal Sanctuary. The Waikato coastal environment also includes Te Whanganui a Hei Marine Reserve on the Coromandel Peninsula and the Firth of Thames RAMSAR site (a wetland of international importance). Habitats and ecosystems range from sheltered shallow estuaries to dynamic open coast beaches, intertidal and subtidal rocky reefs, offshore islands, and deeper water (about 50 to 500 m deep) marine environments.