Pulai River Estuary is 22.6 km long and 2.83 in width. It is one of the largest mangrove forests in Malaysia. In Feb 2003, the Johor State Menteri Besar, Dato Abdul Ghani has declared the area, along with the mangrove forests in Tanjung Piai and Pulau Kukup, as Ramsar Sites.

Pulai River Estuary is originally an ancient wetland. Because it is relatively pristine, its water supports an abundant of flora and fauna.

The tropical eelgrass, Enhalus acoroides, which is also the largest seagrass species in the world extending up to 2 ft in length, can be found in the Pulai River Estuary.

Seagrasses stabilize and accrete sediment ,recycle nutrients, attenuate waves and tidal energy and reduce water turbidity.

The seagrass bed supports a variety of animals, some of them endangered like the seahorse and dugong. The commercially important fishes, crabs, prawns and inverbrates like sea stars, sea cucumbers, anemone etc. also thrive in the seagrass beds.