The blasts occurred in Yala, one of the predominantly ethnic, Malay Muslim provinces in the deep south where a separatist insurgency has dragged on for decades, with more than 6,500 people killed since 2004 alone.
The first bomb did not result in any casualties, but the other two killed one soldier and wounded 18 soldiers and police and two villagers.
“It is believed to be the work of violent groups already creating incidents in the area,” Pramote Prom-in, a spokesman for regional security forces, told Reuters.
As with most violence in Thailand’s deep south, there was no claim of responsibility.
The insurgents are fighting for secession from mostly Buddhist Thailand. Until they were annexed in 1909, Thailand’s three southernmost provinces of Pattani, Yala and Narathiwat were part of an independent Malay Muslim sultanate.