The three-day Songkran festival is expected to generate at least 4.5 billion baht of tourism revenue in 13 provinces.
The Tourism Authority of Thailand (TAT) said the New Year celebrations have been very lively in every province.
TAT governor Suraphon Svetasreni said the festival draws many revellers, especially in 13 provinces where large-scale celebrations partially sponsored by the government are held.
The provinces are Bangkok, Ayutthaya, Suphan Buri, Chon Buri, Samut Prakan, Chiang Mai, Sukhothai, Nakhon Phanom, Khon Kaen, Nong Khai, Songkhla, Phuket and Nakhon Si Thammarat.
Of the expected 4.5 billion baht income, about 2.4 billion baht is expected to come from domestic tourists and the rest from foreign visitors.
But Songkran tourism in the Northeast is down from last year, Samer Jindapong, deputy chairman of the Regional Tourism Federation of Thailand said.
People have less to spend following last year's flood crisis, while higher fuel costs are also taking a toll.
In Nakhon Ratchasima, key attractions in Pak Chong and Wang Nam Khieo districts reported a 50% reduction in accommodation bookings.
He said the Northeast region as a whole could see Songkran revenue dip to seven billion baht from 10 billion baht last year.
In Buri Ram, XXX marked the spot.
Political icon Newin Chidchob imported blue-movie stars from Japan for his extravagant Songkran party at the football field in Buri Ram.
Japanese AV performer Sora Aoi is presented to fans and others at the celebrations in Buri Ram. (Photo by Pattarachai Prechapanich)
Japanese adult video star Sora Aoi joined a stage show at the I-Mobile Stadium of Buriram United FC in a Songkran show credited to Mr Newin. Several other Japanese and Korean "female stars" attended the controversial party.
Conservative critics decried the showcasing of pornographic actors during the festival.
In Bangkok, businesses on Khao San Road have employed at least 50 more security staff, bringing their number to 200 yesterday.
The road has turned into a sea of revellers, about 60% of them foreign tourists, since the Songkran period began on Friday, Piyabut Jiwaramonaikul, president of the Khao San Road business enterprise association, said.
Friday's celebration alone was estimated to have produced at least 13 million baht in tourism revenue for Khao San Road, he said.
But some partygoers have been getting out of hand elsewhere, with complaints of lewd conduct filed with police in Ayutthaya yesterday.
Residents alerted police to a topless transvestite dancer atop a vehicle near Jao Prom market in central Ayutthaya on Friday.
The dancer put on a provocative performance in front of the crowd of revellers and took his top off, revealing his breast implants.
Police arrived later but found the dancer had left the area. He returned after the police had gone.
These are the "approved" version of photos of a transvestite who danced topless in Ayutthaya - and now faces charges of lewd conduct.
Ayutthaya city centre was packed with people throwing water at each other on the main streets.
The inner city zone was off-limits to vehicles carrying large containers of water.