Police said the crash occurred at about 7:30pm on the road leading to Ton Sai Waterfall in Moo 1, Thepkrasattri.
Pol Lt Col Niwat Timket, an investigator at Thalang Police Station, said officers responded to reports that a vehicle had struck motorcycles and people along the roadside, leaving four people injured, two of them critically.
At the scene, police found a black Suzuki Jeep Caribian, registered in Phuket, which had collided with several motorcycles.
The driver was identified as 42-year-old Myanmar national Aung Min Oo.
The four injured were taken to Thalang Hospital by Song Ya Rescue Unit volunteers and hospital rescue workers. They were identified as Thanawich Inkaew, 24; Kanit Promma, 60; Nirun Kochasarnthong, 36; and Mariam Longnawa, 45.
Police said Thanawich told officers that he had been riding his motorcycle from Thalang towards Ton Sai Waterfall when the Suzuki, travelling in the opposite direction, struck him.
According to the initial investigation, the driver continued for about 100 metres after the first collision before crashing into four or five motorcycles parked outside roadside shops, causing further injuries and damage.
Police took Aung Min Oo to Thalang Police Station, where a blood alcohol test recorded a blood alcohol concentration of 239 milligrams per 100 millilitres of blood (0.239 BAC).
At 9:40pm, Thalang Hospital informed police that Thanawich and Mariam had succumbed to their injuries.
Aung Min Oo was subsequently arrested and charged with driving under the influence of alcohol causing the deaths of others.
Police said the investigation was continuing.