Koh Kong has a small, simple food scene. Seafood and Khmer-Thai fusion are the strengths — fish, crab, and prawns come in fresh from the boats, and the proximity of Thailand shows in the menu. Several places along the riverfront and on Street 1 have outdoor seating and English menus.
For breakfast and coffee, the cafes around the central market are inexpensive and unpretentious. For dinner, try a barbecued whole fish (trey aing) at one of the river-facing places — about $8 to $12 with rice and beer. Cardamom Tented Camp and the Tatai River lodges all do excellent set-menu dinners if you are staying out of town.