Phnom Penh’s river front or “Riverside” area as it’s known as by many expats and locals runs adjacent to the Tonle Sap River. Many of the bars and restaurants in Phnom Penh line the road adjacent to the river making this a hive of activity with local food stalls selling fried insects and many of the locals using the space for exercise of to just sit and relax as the sun goes down. Take a walk along from the Naga World hotel and Casino behind the Cambodiana & Himawari hotels all the way up to the night market and you are guaranteed to experience all manner of activity along the way.
At the northen end you can find many boats operating river cruises and tours to Silk Island where the southern end has a ferry port of your feeling adventurous enough to make your own way across to explore Silk Island.
The Tonle Sap is famed for its reverse flow during different times of year. From November until May it flows into the Mekong where as from June until October it flows in the opposite direction due to heavy rain fall.