Cambodia has a largely undeveloped stretch of coastline from the Thai border to the Vietnamese border in the east.
Near the Thai border, some of the islands, including Koh Kong have beautiful beaches but only basic accommodation.
Further east and a two and a half hour drive from Phnom Penh, Sihanoukville is the most developed beach destination in Cambodia. This area and the off-shore islands here are becoming known once again as the Cambodian Riviera.
The beaches around Sihanoukville range from quiet Independence and Sokha Beaches to backpacker-bar lined Serendipity and Ocheteaul beaches. Otres Beach is probably the best beach in this area.
The luxuruious Song Saa Private Island Resort 45 minutes by boat has beautiful private white sand beaches in a marine park.
2018 saw the opening of Golden Sands on Koh Rong, whilst 2019 will see Six Senses Krabey Island and Alila Koh Russey open meaning there will be 4 luxury island resorts on the Cambodian Riviera.
Further east, the unspoilt beaches of Koh Tonsay are just a 20-minute boat ride away from Kep.