The largest wilderness in mainland Southeast Asia, the Cardamom Mountains cover an area of 3,900 sq miles (10,100 sq km). Two regions in these mountains have been declared protected – the Central Cardamom Reserve, which extends over an area of 1,549 sq miles (4,013 sq km), up to Pursat province; and the Southern Cardamom Reserve, covering 557 sq miles (1,443 sq km) east of Koh Kong. These mountains sustain several distinct forest environments and a wide variety of wildlife. Lower  elevations, which are dominated by dry forests and  deciduous trees, support large  numbers of mammals, including the elephant, tiger, and  sambhar deer. This region is also one of the last remaining homes of the Siamese crocodile. Rain forests at higher altitudes are prime territory for endemic species such as the Cardamom banded gecko. Around 1,400 bird species have also been recorded here. However, activities such as hunting,  illegal logging, and land clearance are putting tremendous  pressure on these habitats.

Koh Kong tour operators can help visitors plan trips to the foothills of the Southern Cardamoms. An ecotourism program has been established at Chi Phat village, 13 miles (21 km) upriver from the riverside port of Anduong Tuek, 61 miles (98 km) south of Koh Kong. It offers mountainbiking, hiking, and bird-watching. Local guides trained by Wildlife Alliance, an NGO, organize boat trips to the Chhay Tameas rapids, 4 miles (6 km) from Chi Phat. Visitors are most likely to spot troupes of long-tailed macaques and plenty of birdlife. Another option is the remote park station at Thma Bang, a 2-hour drive west of the Tatai  River, with basic accommodations. Rangers here can organize rain forest hikes, along with local guides.