The annual three-day Water Festival competes with the Khmer New Year for being the most important holiday for Cambodians. The boat races on the Tonle Sap and the carnival atmosphere attract millons of people from all over the country.

In Khmer the annual Water Festival is called Bonn Om Toeuk. The Water and Moon Festival ushers the fishing season. It also marks the reversal of the Tonle Sap river's current. Boat races as well as fireworks are held at the river.

The dates of this festival in 2010 are November 20th, 21th and 22th.
More than 400 boats propelled by precision-trained oarsmen take part in the annual boat race, the highlight of the Water Festival or Bonn Om Touk. This is one of the major events in the Kingdom which attracts multitudes of people from various provinces travelling to Phnom Penh.

The Water Festival also marks a unique natural phenomenon - the Tonle Sap river reverses the flow of its current. It is probably the only waterway in the world which flows in opposite directions at different times of the year. From November to May the Tonle Sap river runs into the Mekong just like any other tributary. But with the arrival of the monsoon rains there is such build-up of water in the main stream that excess pours into the Tonle Sap river forcing it to change direction and flow back into the Tonle Sap lake.

The Festival also coincides with the full moon of the Buddhist calendar month of Kadeuk. The Cambodians believe that the full moon is a good omen which promises a bountiful harvest.
On this night, especially in the countryside people gather to give thanks to the moon. Special food is prepared for this occasion - fruits, vegetables and fish amok, a uniquely Cambodian speciality. Candles are lit, incense burnt and offerings made. The chief priest lights the candles and as it drips on the banana leaves spread beneath the candles predictions are made. It is said that the shape of the melted wax on the banana leaves dictates the state of the future harvest for the year.

It is not surprising that the city takes on a carnival atmosphere during this period. Open-air live concerts are held, food stalls sell a variety of local specialities and children as well as adults take rides on ferries.
Colourful buntings and banners adorn government buildings and as night falls the Royal Palace is brightly lit with colourful lights. Brilliant fireworks illuminate the night sky and flotillas, outlined by lights, glide gracefully down the river.