The water is traditionally a symbol of cleansing for the start of the new year.
 
But there are already worries the festivities could be targeted after a small bomb exploded late on Monday in front of a Bangkok shopping centre.
 
Foreign embassies have urged their citizens to take extra precautions during the holidays.
 
Bangkok blasts
 
Security has been tightened
across the country [AFP]
Army officials have for months warned of possible attacks during the holidays, following blasts in Bangkok on December 31 that killed three and injured dozens more.
 
The authorities initially ruled out any link to a separatist uprising in Thailand's Muslim-majority south, but later conceded that Islamic fighters may have been involved.
 
In February, during the Chinese New Year, there were also a series of co-ordinated arson and bombing attacks which left nine dead and 44 injured in the south.
 
Police blamed those attacks on a group of Muslim fighters they say are responsible for more than 2,000 deaths over the past three years.
 
In recent months, bomb blasts and shootings have become an almost daily occurrence across the four southern-most provinces.
 
On Tuesday a bomb in a busy market in the Yala province left 11 people injured.