The attack happened at 8.50pm on the Joh I Rong-Bukit Road in Ban Joh I Rong village in Tambon Bukit of Narathiwat's Joh I Rong district.
The officers were slightly injured from the impact of the blast that caused chest pain and ringing ears.
They were identified as Pol Lance Corporal Akkarapol Saensira, Pol L/C Chatchai Suanil and Pol L/C Arthit Pasannakan.
Although the insurgents opened fire on the patrol vehicle, the policemen were not hit.
The three were taken to the Joh I Rong district hospital.