Muddy tide flats along with alluvial sand bars characterize the coastline along Manila Bay. Mangrove areas can be observed from Orani to Orion, along with seaweed areas and seagrass patches from portions of Samal, Balanga, and Pilar down to Mariveles. The deeper portions are the coastal areas of Orion to Mariveles. Poor coral reef patches mixed with sandy rocky bottom can be found in the Mariveles area, where the coastline begin to take on a rocky character, looping from the mouth of Manila Bay to the western side of the province.
The South China Sea coastline is interspersed with pristine beaches with rocky portions and fringes of coral reef in good condition from Bagac to Morong. These are havens for marine turtles and other marine animals.