Development within the coastal zone generally may not commence until a coastal development permit has been issued by either the Commission or a local government. The Coastal Act defines development broadly (with a few narrow exceptions), to include not only typical land development activities such as construction of buildings, but also changes in the intensity of use of land or water, even where no construction is involved.

Coastal Development Permits are the regulatory mechanism by which proposed developments in the coastal zone are brought into compliance with the policies of Chapter 3 of the Coastal Act. After the Commission certifies a Local Coastal Program (LCP), most coastal development permit authority is delegated and coastal development permit applications are then reviewed and acted on by cities and counties. In the ports of Port Hueneme, Long Beach, Los Angeles and San Diego, the port governing bodies exercise similar permit authority under certified Port Master Plans. But the Commission has permanent ongoing responsibilities: it retains continuing permit jurisdiction over certain specified lands (such as tidelands and public trust lands), and it has appellate authority over specified categories of development.