Encompassing 82 sq miles (212 sq km) of coastal land, the varied landscape of Ream  National Park includes white- sand beaches, mangrove forests, and the Prek Toeuk Sap Estuary. The park’s marine section comprises the islands of Koh Thmei and Koh Seh, as well as some offshore coral reefs. Thmor Thom, a fishing community consisting of 200 inhabitants, is also located inside the park.

Ream National Park is particularly rich in birdlife with a recorded list of over 150 species that includes the Indian pied hornbill, sea eagle, grey-headed fish eagle, and storks. Its forests are home to sun bears, deer, snakes such as pythons and the king cobra, macaques, silver langurs, and pangolins. Closer to the Prek Toeuk Sap river, visitors may chance upon monkeys and several kinds of kingfisher skimming the water. In the rainy season, it is also possible to catch sight of the endangered Irrawaddy dolphin.

Most visitors explore the national park on a boat trip along the river, which passes through lush mangroves and forests on its way to the sea. Boat trips are an excellent way to view wildlife on the riverbanks. The river also offers good opportunities for swimming close to its beaches. Jungle hikes can be organized with national park rangers who speak English, as it is not possible for visitors to hike on their own.