At least four others were injured in the roadside explosion, suspected to be the work of insurgents, in the southern province of Pattani.
Suspected insurgents on Monday planted a roadside bomb which killed six soldiers and wounded four in the southern province of Pattani in Thailand, police said.
More than 6,500 people have killed since 2004 in a decades-old separatist insurgency in Thailand's largely ethnic Malay, Muslim provinces of Yala, Pattani and Narathiwat. Thailand is predominantly Buddhist.
The latest bomb was planted on a dirt road and detonated as soldiers on a routine patrol were passing, a district police chief official said.
This could be the work of violent groups in the area, the district police chief official said.
Violence in the south typically increases during the Muslim holy month of Ramadan.